Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked and answered on FGF. Special thanks needs to be given to all the FGF members who took the time to respond to other member's questions.
Engine - All
Q: Chrome Air Cleaner for 1967
At some time during my car’s 32 year journey to my garage (1967 400 convertible), a previous owner put an aftermarket chrome air cleaner assembly on it. It fits badly, and tends to interfere with the throttle linkage when the throttle is mostly open (a position it sees all too often 🙂 The only filter that I see listed in the various catalogs that purport to be from 1967 has the louvered pancake style cover. Was this original to the 1967 – 400 car?
A: The chrome louvered pancake air cleaner came on the 1967 Firebirds with a non-AIR equiped 400 CID engine. Firebirds destined for sale in CA came equiped with AIR systems, (emissions control), which necessitated a different air cleaner on the CA 400 cars. That air cleaner was a tradition closed snorkel unit, with the top cover being chrome plated to match the chrome valve covers and breather.
A: I have a 1967 400 with the pancake louvered aircleaner. It was stock on the 400s that year.
A: I have all the original factory chrome on my 400 and the air cleaner is the one you describe. A louvered pancake style. It was also used on vettes. There should also be chrome valve covers, breather and mc cover.
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Content last modified: January 15, 2014 at 1:38 pm
Q: Fuel Sending Unit (2-Line) for 1968 400
I’m getting conflicting stories about a sending unit for my 1968 / 400 / TH400 / air car. Some say only 350 is available, some say only no a/c available, some say it don’t matter. Anyone had to replace one? What can I use for this combination?
A: The difference is the ones with 400 engines and all a/c Birds used a 2 line sending unit, a 3/8 fuel line and a 1/4 return line. The only one available is a single line which they used on 326,350. Someone on the list said they where being reproduced, but I have not seen the name or any information on the vender.
A: I am the one who said they are being reproduced and I have not had time to post all the info but here it is:
Early Birds
Toronto, Ontario
p: 1.800.463.0546
w: www.early-birds.com
e: service@early-birds.com
Catalog page 65 part number 6428846 1967, 1968, and 1969 dual line sending unit price is $175.00 plus our tax of 15% this price is Canadian. They do their shipping through UPS but expect it to take an extra day for a border crossing. Also the exchange rate right now is about 50 cents on the dollar so an American dollar is worth about $1.50 here so you can figure out about what it would cost.
also just a note we had ours rebuilt by a gas tank repair shop for $181.00 they sandblasted our tank , flushed it, painted it and rebuilt our sending unit. So maybe you would want to check that out also
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Content last modified: January 16, 2014 at 6:13 pm
Q: Dual Port Advance for 1968
My 1968 is missing the dual port advance. Is this part necessary?
A: The purpose for the dual port advance was for early emissons and with the redesign of the 1968 heads that are supposed to sacvange the fuel and air to burn cleaner.
A: Dual port advance mechanism was actually a retard and advance unit in one can. Tech bulletin I have states that some owners complained of popping in the exhaust due to the retard. Most dealers disconnected the retard and sent the customer on their merry way
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Content last modified: January 15, 2014 at 1:39 pm
Q: Fuel Guage Sending Unit Sock
A few weeks back I was looking for information on how to replace the sock on the fuel gauge sending unit. Anyone ever done it? Is it hard to do? Got advice????
A: This weekend, I took a look at my sending unit. The sock was missing, so there was little filtration going on in that fuel system. But the retaining ring that held the sock in place was still there. There were traces of the sock mesh on the edges of the ring, so it looks like it had been torn off. No sign of the sock in the gas tank. Judging by the ring I saw, and pictures of the sock in various catalogs, it would appear that the sock simply slips over the end of the pick-up tube. The sock has a built in ring at the open end. I was able to remove the sock ring with no difficulty at all. Installation should be a simple slip fit.
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Content last modified: January 16, 2014 at 6:14 pm
Q: Vacume Hose Diagram for 1968
I am in need of the vac hose diagram for my 1968 350 ho with the dual vac advance. No a/c or air pump. The advance has been replaced with a single port which is WRONG so I want to put it back right along with the plumbing. Thanks in advance.
A: I don’t have a complete answer but maybe this will help.
There should be a themostatic control switch which mounts on the passenger side of the intake. It will have 5 ports on it. One (DA) goes to distributor advance. One (DR) goes to distributor retard. One (CA) goes to carb advance – I don’t know which this is but I think (??) it is ported vacuum. One (CR) goes to carb retard – I don’t know where this is. The last one goes to to manifold vacuum (at the bottom rear of the carb). If you have an Automatic, the vacuum modulator also goes to manifold vacuum.
Also, the AMES catalog sells both the control switch ($35) AND correct color vacuum hose kits ($54 – ouch). They also have a pretty good diagram of a 1968 4bbl in their catalog and I’m guessing they send directions with the kit.
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Content last modified: January 15, 2014 at 1:40 pm
Q: Lead Substitute
On my 1968 Firebird 350, is lead substitute added to gas recommended?
A: I add it to my 350 and use octane 92 gas. I do both to increase the octane levels the engine was originally designed to run on. This recommendation started when I started having acceleration and knocking problems when I finally had to switch to unleaded back in the mid 80s.
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Content last modified: January 16, 2014 at 6:15 pm
Q: Vacuum Hose Diagrams for 1968
Hello all! I am in the midst of rebuilding my 1968 firebird 400 conv. (little by little). I am working on the engine for now, while I am waiting for my Year One parts to arrive… I read the message a little earlier about overheating. Which unfortunately, my poor car is doing! It mentioned the vacuum advance hose being on ‘manifold’ rather than ‘ported’ vacuum. I was wondering if anyone might be able to point me in the right direction for a Diagram of CORRECT vacuum hose routing (or some dang good pictures), for a 1968 400. It seems the owner before me, decided to just cap off almost every vacuum port available… so this could be one cause of the overheating… ?
A: Pictures of the diagrams:
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Content last modified: January 15, 2014 at 1:47 pm
Q: Octane Level
What octane rating should I use in my Firebird? I’ve always been told to use the lowest octane fuel available – seems to work for me.
A: The thing to do is to use the lowest octane possible that does not cause detonation (pinging). There are too many factors that control this some being distributor advance, compression ration, carbon build up in the combustion chamber, carburetor adjustment, plus a bunch more. Each car is different so you have to either start at the bottom and work your way up or start at the top and work your way down.
Today’s cars have microphones attached to the blocks that listen for detonation and adjust retard accordingly via the computer. Our cars don’t so you need to use your ears.
You certainly won’t hurt it by using 92 (or higher if available).
A: You are on the right track, but it would make more sense to use the lowest octane fuel that doesn’t make your engine ping or knock. You will eventually break something if you used a lower octane fuel just because it was available.
There is no hard and fast rule saying that you must run a certain octane fuel in your 1st gen car. You must experiment and see how it runs with what’s available. If it knocks with 85 octane, then try 87. If it then runs fine, stay with that grade fuel. Using a higher octane than necessary will not benefit you car, and will even raise it’s pollution output.
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Content last modified: January 16, 2014 at 6:16 pm
Q: Premium Gas Usage
I got to thinking about octane while I stood and watched the $$$ go by on the gas pump today. What determines the need for a higher octane? Is it the compression ratio? The HP? Torque?
I was wondering if using premium fuel is necessary. Maybe someone has some knowledge on the subject. BTW, I have a 350 with a 4-bbl, and I have been running 92 octane in it ever since I’ve has the car. In its original 2-bbl configuration, it is billed as a “regular gas” engine.
A: Compression ratio determines the need for octane
John Sawruk spoke on this at the POCI nationals. He qualified all the Pontiac V-8’s as a Pontiac engineer. He said the pre 71 (10:1 compression range) engines were qualified on 100 research octane. Sunoco Ultra 94 (pump rating) is about 98 research. He felt 94 plus a can of booster was about right. He said to be careful about preignition that you can’t even hear. He also strongly recommend changing all hoses that come in contact with todays gas and/or vapors.
A: The engines that required Premium fuel in 1968 must have the hights octane put in plus an octane booster. These engines included the HO, Sprint, and Ram Air engines.
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Content last modified: January 16, 2014 at 6:17 pm
Q: Aviation Gas
I have an HO engine which requires premium gasoline. Now that gasoline has lower octane rating and no lead, I want to possabley use Aviation Gas. Doesn’t AVGas burn pistons over time? What about Cam 2 or 3? I’ve heard Sunoco has a higher octane fuel for this application.
A: You may have wanted a simple ‘yes’ or ‘no’ answer, if so: ‘no’. But since I have done a fair amount of research/experimenting with gasoline and find it a very interesting topic, here goes!
AV gas itself will not burn pistons. But this is not to say you cannot burn a piston with AV gas. AV gas is higher octane than typical pump gas but it is typically formulated to burn at higher elevations. Also, the vast majority of aviation gas is unleaded or “low lead” (nearly unleaded). As with any fuel, you need to jet your carburetor (or fuel delivery system) to correspond with the specific gravity and other characteristics of the particular fuel. Simply adding higher octane fuel to a properly tuned car will rarely increase performance, any usually degrade it. The reason you can make more horsepower or go faster with higher octane fuel is that you can tune your motor to take advantage of the particular fuel. That is, you can run higher compression and more advance with higher octane and, thereby, make more power.
If you’ve even seen Chevron’s commercial where they say something like you can make more power with their Supreme gas, you will note A LOT of disclaimers at the bottom of the ad. Basically, this only applies to cars with fairly sophisticated engine management systems. That is, ones that increase ignition advance until the sense knock and then slightly back off. With this sort of engine management system, a higher octane fuel will actually more the car go faster. While is seems counter intuitive, a typical engine will make more power using the lowest octane possible fuel (lowest so as to prevent detonation, that is). Once you exceed this level, performance will actually drop off. Many people will argue this, and may even produce time sheets showing better ET’s, but when driving on the street, there are far to many other variables. You will not see an improvement on a dyno, only a decrease.
Another concern is that AV gas is not taxed for use on the street and thus using it on the street is illegal. No FBO will pump AV gas in your car. While they will pump it in drums and you can transfer them to you car, it will still be illegal to use it on a public road. Should be o.k. on a race track but you will be far better off buying a race fuel specifically formulated for your application.
AV gas used to be a more viable alternative, but still not the best choice, when it was leaded. This is because it got most of its increased octane due to the addition of tetraethyl lead (“lead”). When mixed with pump gas or even real race gas, a significant increase in octane would occur, thereby allowing the use of higher CR’s and more spark advance.
Contrary to someone’s earlier post, there is no magical compression ratio cut off for running on pump gas. Your engine’s octane requirements are dependant on far more variables that just CR. Squish band, combustion chamber shape and layout, timing as well as even the material of your head (cast iron vs. aluminum) all make a significant difference. There is no reason you cannot set up an engine to run 10:1 on pump gas (I believe Jim Hand has done this with his wagon but an not 100% confident on this and too lazy to check right now!!). Obviously there WILL be an upper limit but it is unique to each combination. I probably would not encourage someone building an “average” street motor to go much higher than 9.25:! but this is based on the complexity, care and expense necessary to set up an maintain a motor running a higher CR on low octane fuel. Also, there is not that much power that will be gained going from a 9.25:1 to a 10:1 CR.
Sunoco does sell their GT100 fuel in some areas (check out www.racegas.com). This site also lists specifics details on their race fuels as well. VP also makes a variety of high quality fuels. If you are looking for high end race fuel (gasoline, not nitro methane) you can also try Elf or Nutec.
Fuel technology is incredibly complex and very interesting (at least to me)! If you go to a GP (car or bike) you will notice that the top team have fuel technicians that ‘brew’ fuels for not only each track but to correspond to the environmental conditions change through out the weekend.
A: As a Petroleum Engineer I can only say, “very informative and well said.”
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Content last modified: January 16, 2014 at 6:18 pm
Q: Thermostatic Vacuum Switch (TVS)
My 1968 400 Firebird has what I believe to be a vacuum switch on the intake manifold and there is at present nothing connected to it. Should there be? One would think there should. I have no idea what to hook up to it as all of my vacuum lines seem to be accounted for. Any helpful suggestions would be greatly appreciated.
A: Yes, it should be there. Should it be hooked up? If you want it totally stock yes. Is it necessary? Probably not, especially if someone has replaced the vacuum advance unit (regulating vacuum to the distributor) on your distributor and you don’t have a dual port unit anymore.
If you did want to hook it up, there should be five ports and they go something like this, I think:
Inputs: Carb Advance, Carb Retard, Manifold Vacuum
Outputs: Distributor Advance, Distributor Retard
If you want to hook it up and be sure, get the vacuum line kit from AMES and ask them for directions (if they don’t come with it).
A: It is what’s known as a thermovacuum switch.When the engine coolant temp is below the temperature rating of the switch certain ports are open to each other allowing vacuum to flow between them.Once the temp rating is exceeded the thermal pellet raises a rod inside & switches the vacuum to different port(s).This switch works very much like a thermostat.They are used for many different purposes on cars,in some cases they delay operation of some device (an EGR valve for example) until operating temperature is reached (to avoid stumbling & “sag”),other times they are used to operate a device only until operating temperature is reached (example- a vacuum operated heat-riser valve).
A: Here is the text of an article that AME’s FAX’d me. Looks like it was from Pontiac Enthusiast magazine (Vol. 1 No. 2) and was written by Peter Serio:
Back when emissions systems first appeared on cars, it was almost an instant reaction to open the hood and say, “Who needs this stuff to slow my car down? Let’s rip it out, plug the holes, and go faster!” Years later, it may become mandatory for vehicles manufactured in the early days of emissions systems to have fully functional systems in place. In addition, in concours competition, a deciding factor can be a detailed engine compartment with a correct and operational set of emissions parts. In addition, your car’s drivability could depend on an understanding of how the emissions gear works. In the previous issue of Pontiac Enthusiast, we looked at the 1968-69 manual transmission vacuum advance valve. In the next issue, I will cover the transmission-controlled spark systems used from 1970-72. For now, it’s time to turn to the TVS, or thermostatic vacuum switch.
The TVS-GM#3016754 is used on all 1968 V8’s and on 1969 V8’s with automatic transmissions. Also, several early production 1969 Ram Air III cars with manual transmissions were built using the TVS and the vacuum advance valve. The 1971 455 HO engine also used the TVS with either transmission.
In all applications, the TVS serves as a safety device to help prevent overheating. The switch is located at the front of the intake manifold, threaded into the coolant passage. There positions inside the TVS related to coolant temperature. Standard vacuum flow is ported vacuum from the carburetor to the distributor vacuum advance. Whenever the engine coolant temperature rises above 230 degrees F, the TVS switches the distributor advance from ported to full manifold vacuum. This advances the timing about 20 degrees at idle, allowing the engine to cool down to normal operating temperature. After the engine cools, the system returns to ported vacuum.
If your car does not have the system hooked up properly, it could overheat on a hot day when you’re stuck in traffic, which could reduce the life of your engine. In 1968 the fan shroud become standard for the GTO, whereas in earlier years it was an option on non-air cars. With the idle retarded in 1968 to reduce idle speed emissions, the switch’s purpose was to advance the timing when necessary to allow the motor to cool down, to prevent pinging.
A manifold connector in the vacuum hose harness to the TVS is used to prevent the hoses from being installed improperly. Note that some of the vacuum hoses in the harness have color-coded stripes running on the supply lines to the TVS. The red-striped hose is manifold vacuum, and the ported vacuum is routed through a small steel pipe forward of the carburetor. The yellow hose (used in 1968 only) is the retard-at-idle-speed vacuum supply.
There were two different hose harness assemblies used, depending on the year of the car. In 1968 only, with the dual-port vacuum-advance unit attached to the distributor, the idle speed timing is retarded 10 degrees to reduce emissions. After the 1968 models, all distributor-advance units were the standard single-hose-connection style. All the ’68s use the 5-hose vacuum harness, while the 1969 V8’s and ’71 455 HO make use of the 3-hose type. The two extra hoses on the ’68-only harness are the idle-speed retard feature.
Apparently it did not take long for dealers to receive complaints that some of the 1968 cars idled poorly, and Service Bulletins 68-T-2 (dated 10/16/67) and 68-T-2A (dated 1/4/68) were released. Models affected were the 1968 Firebird, full-size, and Tempest/LeMans/GTO with the 2-barrel carb and automatic trans, plus full-size automatics with the 4-barrel. The complaint was that the second-to-first downshift could clunk badly due to the retarded timing. Manual-transmission cars were unaffected, since the idle speed was higher and you shift your own gears. The procedure outlined in the bulletins basically involves removing the two vacuum hoses that retard the timing at idle; shortening one and connecting it to the two switch holes in a U to keep dirt out of the holes; and readjusting the idle speed. If you have a 1968 2-barrel automatic or full-size 4-barrel automatic, these Service Bulletins would be a nice item to search for.
A:
________ / \ | (1) \ | \ | (4) | | | | (2) | | | | (5) | | / | (3) / \_________ /
-
(1) To vacuum port on front of carb (steel routed line)
-
(2) To “Tee” at rear of carb
-
(3) To distributor advance
-
(4 and 5) are looped together at switch.
A:
From the 1968 Diagnostic Manual:
Fig 6D-9 Components of Controlled Combustion System
[pdfjs-viewer url=/files/FAQ/docs/6D-9.pdf viewer_height=800px fullscreen=true download=false print=true]
Fig 6D-10 Distributor Vacuum Layout V-8 2 Bbl.
[pdfjs-viewer url=/files/FAQ/docs/6D-10.pdf viewer_height=800px fullscreen=true download=false print=true]
Fig 6D-11 Distributor Vacuum Layout V-8 4 Bbl.
[pdfjs-viewer url=/files/FAQ/docs/6D-11.pdf viewer_height=800px fullscreen=true download=false print=true]
Fig 6D-12 Vacuum Routing Chart
[pdfjs-viewer url=/files/FAQ/docs/6D-12.pdf viewer_height=800px fullscreen=true download=false print=true]
Fig 6D-13 Vacuum Routing Chart
[pdfjs-viewer url=/files/FAQ/docs/6D-13.pdf viewer_height=800px fullscreen=true download=false print=true]
Fig 6D-14 Vacuum Routing Chart
[pdfjs-viewer url=/files/FAQ/docs/6D-14.pdf viewer_height=800px fullscreen=true download=false print=true]
A: Jim, a list member from the First Generation Firebird-L Mailing List, did research on this compairing all the documents available and put together his findings:
[pdfjs-viewer url=/files/FAQ/docs/TVS/68VacuumDialog.pdf viewer_height=800px fullscreen=true download=false print=true]
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Content last modified: January 15, 2014 at 7:59 pm
Q: Gas Tank Venting for 1968
Does anyone know how the gas tank vents on a 1968 convertible with a 350/auto??
A: It used a vented cap.
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Content last modified: January 16, 2014 at 6:19 pm
Q: Gas Tank Venting for 1969
I just picked up a 1969 Firebird w/ a 350 2bbl, 350 turbo Trans, PDB, PS, & A/C. This is the third 1969 I’ve owned but the first 350. I was removing the gas tank to replace the trunk and noticed that this tank doesn’t have the little vent tube that the 400s had just below the cap. Is the vent tube unique to the 400s or the H.O.s?
A: I have an original 350 2-barrel car (convertible) and I just checked it today. There is a small tube which connects to the filler tube just below the cap. The tube is about 6-8 inches long, it turns around in a “U” and then connects to a fitting just above the filler tube on the body. Hope this helps.
A: I have had a few 69s with and wthout the tank vent, checked my friends OHC-6, A/C car and it has one. So not just 400 cars got this I think its a production change early in the year but I believe that a/c cars got it (never say ALL) regardless of motor.
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Content last modified: January 16, 2014 at 6:20 pm
Q: Distributor Vacuum Advance Valve Assy
Was the Vacuum Advance Valve (control) only on Firebird’s, or was this also on GTO’s ? Was it installed on any `68 Pontiac with any manual trany ?
A: The Distributor Vacuum Advance Valve Assy was used on all 1968/1969 Pontiac’s with Manual Trans and the 1967 M.T. A.I.R. engines. # 9773623. It was attached to the RH Rear of the Intake Manifold. The Plastic Cover on the end should be Black. On the RAII engines, this cover was Green (#9794257).
This should not be confused with the Distributor Vacuum Control which attached to the Distributor itself. Both are available NOS now & then.
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Content last modified: January 15, 2014 at 2:11 pm
Q: Gas Tank Paint
I have the gas tank out of a 1969 Firebird which I’m replacing the rear end on. I want to clean it up nice before putting it back in. Question is, how is the gas tank supposed to be finished? Body color paint? Black paint? Undercoating?
A: Original color was silver (galvanized). Eastwood company sells a close duplicate color.
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Content last modified: January 16, 2014 at 6:21 pm
Q: Dual Diaphragm Distributor
I am having a problem with a slight backfire and someone told me to disconect one of the two hoses to the distributor. Is this correct?
A: 68 was the only year for a dual diaphragm (advance /retard) distributor. It was to retard the distributor under certain conditions for emission lowering. A service bulletin was issued for dealers that got complaints to disconnect the retard side. A lot complaints of a slight backfire on coasting downhill and deceleration . Such a tech service bulletin wouldnt be issued today as theres a stiff fine for modifying or removing any emission device Chances are the retard side has been disconnected on yours. Look for a separate vacuum hose nipple on the distributor advance/retard control “thingy”.If its been removed,hope that the vacuum source has been plugged off.
From the Pontiac Service Information Bulletin:
[pdfjs-viewer url=/dtb/docs/68-T-2.pdf viewer_height=800px fullscreen=true download=false print=true]
[pdfjs-viewer url=/dtb/docs/68-T-2A.pdf viewer_height=800px fullscreen=true download=false print=true]
[pdfjs-viewer url=/dtb/docs/68-I-45.pdf viewer_height=800px fullscreen=true download=false print=true]
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Content last modified: January 15, 2014 at 7:55 pm
Q: Fuel Line Routing for 1967
Can any one tell me how fuel gets from the right side of the eng compartment where me fuel line stops to the left side where the fuel pump is..thanks it’s a 67
A: The fuel lines on a 1967 run along the inside of the right sub frames from the rear of the car and cross over to the left side of the car along the crossmember of the front subframe. Unfortunately, the Firebird service manual does not have a fuel line routing diagram in it which shows the exact placement.
A: There is another fuel line that follows the crossmember under the engine. It joins the “camaro” fuel line with a short rubber hose, and there is the usual hose to the fuel pump. This fuel line is held by the same clips as the brake line for the right front wheel. Mine’s a 1968, but they’re probably the same.
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Content last modified: January 16, 2014 at 6:21 pm
Q: Firebird Q-Jet ‘Tab’ for 1967 / 1968
Does anyone have information of the bent tab used to limit the horsepower for the carburetor found on the 400 Firebird.
A: For many years, it has been widely accepted that the major difference between the 400 Firebird and GTO engine (1967-1968) has been the carburetor. Factory/Dealer specs listed the Firebird 400 at 325hp for 1967 and 330hp for 1968. The GTO was listed as 335hp for 1967 and 350hp for 1968. All 400 HO & Ram Air engines for both models were listed as 360hp for 1968 (1967 Firebird RA was listed at 335hp).
No where in the factory/dealer literature is there a mention of a different throttle bracket, tab or linkage preventing the Firebird secondaries from opening as far as the GTOs.
There have been several articles & publications over the years that have refered to such a variation on the Firebird Carb.
Hot Rod Magazine- 3/68 “…in order to produce the advertised horsepower, there is a small tab on the throttle shaft which actuates the secondaries, but only to two-thirds open at full-throttle. Somehow you don’t feel guilty at bending it rearward.”
Special Interest Autos- 10/86 “..The 400 was detuned to 335bhp by adding a small metal tab in the throttle linkage which slightly limited travel of the secondaries. Needless to say, very few of these tabs remain today where GM put them.”
Motor Trend- 12/91 “…GM only agreed to install the 400 engine if it could restrict it’s performance, which meant it placed a stop on the throttle linkage that prevented wide-open throttle. Of course, that could be removed by the owner in about 30 seconds.” (Jim Wangers)
The Fabulous Firebird- M.Lamm- 1979 “…Yet to stay within GMs horsepower ruling (1hp for every 10lbs), Pontiac not only derated the Firebird 400 V-8 to 325 bhp but also modified it so, in showroom form, it truly wouldn’t produce more than 325 bhp…. by simply changing the link between the primary and secondary barrels of the Rochester Q-Jet carb. This link was arranged with a steel tab that didn’t let the secondaries open more than 90% at full throttle.”
Firebird Decoding Guide- T. DeMauro- 1997 “A throttle linkage restrictor installed on all Firebird 400s stopped the rear two barrels of the Quadrajet from opening allthe way, thus limiting horsepower and keeping the car within the 10-lbs to 1 hp Gm corporate edict.”
So, as you can see, there was obviously something different between a GTO carb and a Firebird. Surely all of these articles were not simply created from simple rumors or suspicions but from experience. Many references were based on modifications by Royal Pontiac during prep for an article (to squeeze out more performance). No mention was ever made about the difference in the exhaust system. If anything, the HO and Ram Air Firebirds had a better exhaust system due to to Long Branch Exhaust Manifolds.
As for defining the actual component on the carb. and how it was different, there needs to be a photo comparision to better explain this. The above excerpts seem to refer to the same thing; a tab on or a part of the throttle linkage.
I am currently going through my files and pulling up detailed photos and illustrations I have pertaining to this matter. If anyone has an original ’67/’68 Firebird 400 4Bbl Carb. and wouldn’t mine taking a few close-up photos (RH & LH side), I would be glad to follow-up on this and post the final comparison photos.
A: I seriously doubt that the Rochester plant earmarked certain carbs for Firebirds and bent the tabs. How would you explain the carbs that the GTO and Firebird both share same part #? Same part # means same part. Period….
The reason for different part #s of certain models of Firebird vs GTO was that the jetting was different. Base plate assemblies which have the throttle linkages attached are the same part #s between GTO and Firebird.
A: After initially researching this through careful examination of original, unrestored cars, an extensive detailed photo collection and checking the carbs I (and friends) have, I too was convinced that both Firebirds and GTO carbs were assembled using the same Rochester components. The only possible explanation would be that the lower tab on the inner Throttle Link could have been bent to prevent full travel however, I did not find this in my research (all have been corrected ?).
Then, I received a reply from Paul Spotts who claims to have an unrestored Firebird carb with this modifed (bent) tab in place. He also says this link was a different part number and that he submitted an article to HPP that explains in detail (w/photos) this entire issue. So, I guess we’ll wait and see if it gets published. In the meantime, I’m continuing the search.
As for the shared part numbers for GTO & Firebird, I’ve noticed that over the years (following production), different Parts Catalogs start combining the usage for carbs (typical service replacement procedure).
Also on a related note, I recently came across an early ‘take-off’ 7028277 RA I carb and spent a great deal of time comparing it to a 7028267 carb I have. Other than the Rochester I.D. stamp (for specific usage), there was absolutely no other difference with regard to Rochester component numbers. Every stamped or cast number was identical on every piece. Interesting.
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Content last modified: January 15, 2014 at 8:05 pm
Q: Fuel Line Replacement
Where do I find replacement fuel line for my Firebird?
A: If you can’t find a used/new line, consider the mandrel tubing bender in the Sears Automotive catalog. It costs about $60. then just by fuel/brake line at the parts store and build your own. I bent the fuel lines for my Firebird and Bonneville with this (fuel pump to quadrajet). Looks exactly like the factory line. By bending one for each car, I figure the tool paid for itself.
Warning!: If you’re like me, you’ll probably need several pieces of this line just to get the hang of how the tool works. You know the old saying, “measure twice, cut once.” Holds very true with this. It may be your only source for a correct type fuel line. Besides, it’s a lot of fun, really!
A: Fuel lines are available for 67-9 repro or you can do as Greg says and make your own. You can buy the steel line in 25′ roll at auto parts store(look around someone will have it ) Roll the required length out before starting, add a couple of feet extra and cut off the roll. I get my line straight by rolling out on the garage floor using a friend to hold end for the first couple feet, push down while rolling and you wont get any humps. Just curious but how did you barb the ends where the rubber lines are attached? This is necessary to insure that rubber line doesnt slide off and seals properly. I’ve been looking for the swedging tool to do this. Also if you buy repro line make sure it has this feature.
A: To barb the end of the tubing, use a double flare kit. Insert the reverse flaring die into the end and tighten just enough to create a bulge. Hose will not slip off.
A: The barb on the ends is easily made if you have a flaring tool with the adapter for double flares for brake lines (you must use double flares for brake lines!) Just do the first step of the double flare and you have a barb. As for the shape, just follow the existing brake line on the cross member, and get within 3 inches of the Camaro line so the rubber hose isn’t too long. Have fun!
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Content last modified: January 16, 2014 at 8:11 pm
Q: Date Code on a Carburetor
On 1968 quadrajets, where is your date code stamped? Not on the body next to the Rochester number, but on the base, right? Anyone with a 1969 have it on the base also?
A: …I’ve seen and have (or had) 1968 Rochester Carbs with the Julian Date Code stamped near the Model Number on the Body and on the Base at the back. I’ve also seen them with no date code at all (RA I 7028277). I suspect that early 1968 Carb’s were most likely to not have the date code or for it to be on the Base.
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Content last modified: January 15, 2014 at 8:07 pm
Q: Gas Tank Strap and Finish
I dropped the tank off to get clear coated. I read they came un-painted. As well as straps. True?
A: According to the “Camaro Restoration Guide, 1967-1969” by Jason Scott, the gas tank should be natural galvanized steel, while the straps ought to be either natural steel finish or gloss black. Given that the Camaro and Firebird share so many common parts, the fuel tanks and straps among those, it would be safe to assume the finish is the same. To cross reference, I checked my GTO restoration guide by Paul Zazarine, but it is silent on the subject of 68-72 fuel tanks.
You can get some spray can galvanized coatings for the tank, or Eastwood’s own tank coating. Watch out for some of those galvanized look paints. One type I bought at the hardware store went on very dry and looked terrible. I ended up recoating with something else. For the straps, try base coating with POR15, then top coat with Eastwoods “Fresh Steel” paint, or a gloss black.
It was my experience when reinstalling the fuel tank, that the new rubber strap insulators didn’t want to cooperate in staying in place while raising the tank and bolting it in. Try using an adhesive such a the 3M weatherstip cement (Gorilla Snot) to keep them in place.
A: The reason the rubber on the straps doesnt work,is because is not the way the factory did it. The factory used a tar impregnated material just like thick tar paper. It would stay in place when the straps were tightened where as the rubber tends to shift around. Also the rubber may be a source of squeaks whereas the tar paper stops squeaks.
The correct finish is bare steel straps and galvanized tank.However clear coat would be a way to keep lookin fresh. I removed my original 1968 tank for a clean up, and it was coated with a paraffin based under coating when new. It wiped clean with mineral spirits and looks like new. I also found some green crayon markings that the factory used for assembly identification.
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Content last modified: January 16, 2014 at 8:12 pm
Q: Sprint Radiator
What is the correct radiator for a Sprint engine? I am worried I do not have the correct one since I keep over heating plus someone mentioned my Sprint is missing “Filler Panels.”
A: Single core is correct for a 1968 Sprint, unless it had the HD cooling. Radiator should have a metal tag with the letters “ZA”. Code for the HD unit is “UF”. A 3 core from a 350 V-8 will fit right in the same location.However the finger guard may not. OHC-6s dont use a fan shroud. I think the radiator you have is clogged or in poor condition. I’ve never had an overheating problem with any OHC-6s.
A: The Filler Panels are the panels that go between the core support and the front bumper support.
They were installed in 400 cars and A/C equipped cars. The idea was to force as much air as possible through the radiator, instead of having it “leak” out around the bumper. They can be bought as repros, if you’re interested in using them.
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Content last modified: January 15, 2014 at 8:37 pm
Q: Fan Hits Shroud
I just bought a new Radiator and Shroud from Classic Industries for my 1969 350 TH350. The radiator is an exact fit in the car and matches the one I took out. The shroud fits nicely on the radiator but I didn’t have a shroud before so I don’t have one to match up. When I installed them I could see right away that the fan touches the Shroud at the bottom. The Shroud is 21 1/2″ and the fan is 19″ as they should be but I have 0″ clearance on the bottom and 2 1/2″ clearance on the top. Left to right is good.
Any ideas why it doesn’t match up good? Only thing I can think is that the water pump is incorrect and has the mount for the fan too low compared to original……any other ideas?
A: It may be the pulley, possibly your engine is slightly off center?
A: You Probably need new motor mounts. I had the same thing happen on my 1968. The rubber in the mounts gets squished after many years.
A: The following things come to mind:
1) Have the engine mounts ever been replaced?
2) Are the body bushings between the front sub-frame and the body original? If so, do they need to be replaced? If not, are the replacements the same height as the originals?
3) Are the body bushings between the front sub-frame and the core support original? If so, do they need to be replaced? If not, are the replacements the same height as the originals?
4) Same applies to the transmission mount.
Any or all of these could account for the motor sitting 1″ – 2″ lower than it should which would result in what you are seeing. I don’t think the water pump has anything to do with it.
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Content last modified: January 15, 2014 at 8:40 pm
Q: Shroud Fit
Since buying the car, my wife’s 1969 bird has had a mismatch between the fan and the shroud. For some reason the fan sits too low in the shroud and rubs against the bottom. In fact, I had to clip the bottom of the shround to avoid the rubbing. The fan is 2 inches smaller in diameter than the shroud, so it should have 1 inch gap on the top and bottom, but instead it has 2 inches at top and zero on bottom.
A: Take a look at your front subframe bushings, for the radiator brace. What you are reporting sounds like these bushings are compressed and have caused the front sheet metal to droop.
A: I’ve thought of that too, but wouldn’t that cause the radiator support to drop, which would make the shroud too low? My problem is the shroud is too high.
A: Actually, it’s probably just the opposite. The fan is rubbing on the bottom so the bushings would have to be too tall.
Something simple to check is to verify that the clips holding the bottom of the shroud against the radiator and fully seated and that the shroud is sitting all the way into the clips. I have also found that the shroud will sometimes hit the lower radiator hose or the pit-cock and will keep the shroud from staying in it’s proper location.
I had a similar problem when I put my 1969 back together. I rubbed on the right side near the battery before I took it apart. After I put it all back together, using the existing bushings, I gained 1/2 of clearance. I think it was just due to a combination of moving things around.
You may also want to check that you have the correct transmission mount or that the transmission cross member isn’t bent.
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Content last modified: January 15, 2014 at 8:41 pm
Q: Fan Pulley Diameter for 1967
Whats the proper diameter of Fan Pulley for a 1967?
A: Keep in mind that there are 8 different belt and pulley configurations for a 1967 V8 car! I’m assuming you’re asking about the car noted in your tag line. The 1968 and 1969 V8 cars have only 4 possible configurations.
1967 V8 Pulley and Belt Applications (assume each config. has an alternator)
1. Standard car (no accessories)
p/n 544595 8 inch
2. Power steering only
p/n 9786819 8 inch (two groove)
3. Air conditioning only
p/n 9786909 7 1/8 inches (two grooves)
4. Air conditioning and power steering
p/n 9786909 7 1/8 inches (two grooves)
5. Air injection (A.I.R.) only
p/n 9786819 8 inch (two groove)
6. Air injection and power steering
p/n 9786819 8 inch (two groove)
7. Air injection and air conditioning
p/n 9788886 5 11/16 inch (two groove)
8. Air conditioning, power steering, and air injection
p/n 9788886 5 11/16 inch (two groove)
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Content last modified: January 15, 2014 at 8:43 pm
Q: Lower Radiator Hose for 1969
I have a 1969 350ci with TH350 and NO A/C. Just bought a lower radiator hose from Ames and it didn’t fit. It was a 1.5″ I.D. hose with a flare out to 1.75″ at ONE end. It didn’t fit for two reasons. For one, it was too long and didn’t physically fit in the car. For two, both my water pump AND radiator need the 1.75″ I.D. hose.
Anyone else ever have this problem or is there something wrong with my car?
Anyone know what size hose they use on their car or where they buy them from and what the Part Number is?
A: I just bought and installed a lower radiator hose on my 1969 350ci TH350 with A/C. The hose was the same size on both ends. Without measuring it I would assume it is 1.75 inches. The hose was not very long, I would guess 15-18 inches. At any rate, I picked it up at the local NAPA auto parts store. This was about the only store in Austin that stocked the lower hose.
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Content last modified: January 15, 2014 at 8:45 pm
Q: Heater Hose Replacement with A/C
Does anyone have any suggestions on how to get the heater hoses on the heatercore on a 1969 firebird? Oh yeah, it does have air conditioning……………..
A: It’s one of the added pleasures of having an air conditioned GM car…..
Heater hose connections can be accessed from under car. Take a couple of fender skirt (inner fender) bolts loose and shove a piece of 2×4 between it so you can reach up to the hose connections. Take care not to break loose the tube that goes to heater core, otherwise you might as well pull the fender to replace heater core. If you split the old hose with a razor knife it will come off much easier.
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Content last modified: January 15, 2014 at 8:46 pm
Q: AC and Ram Air
Was the AC option available on a 1969 Ram Air?
A: for what its worth, ac was avaialble on both auto and ac cars in 1969 (not true for 1968 see below).
However, NONE of the true ram air cars ever received factory AC. (ie 1967-1968 ram air I, 1968 ram air II or 1969 ram air IV equipped cars)
now the 1969 400HO cars (dubbed ‘ram air III’ in 1969 when you also added cold air induction option) could get AC no matter what tranny you ordered…
why? well im guesing because the RA III cars, aka 400HO in 1968, were esssentially standard 400 cars (especially the auto equipped “RA III/400ho” cars). Outside of the longbranch manifolds all 400ho/ra III all cars received, they were pretty much std 400 cars (ie no mandatory 3.90s, no special 400 heads, no upgraded cam, no beefier lower end (all 2 bolt mains), etc)
note: the manual 1969 RA III s DID get the upgraded 068 cam but not much beyond that. so since RA III cars were very close to std 400 cars mechanically/performance wise PMD must have figured that it was ok to get ac for these cars.
Please though, no RA III flames! the pontiac 400 is an awesome block in *whatever flavor* it originally came in! its just that i think the ‘RAM AIR III’ monaker is a bit misleading to many espeically since its ‘numerically higher’ than RAM AIR I and II.
1968 manual tranny and ac…
ama specs show that pontiac did NOT offer ac if you ordered a manual gearbox in 1968 note however that this was NOT true in 1967 and 1969 when ac and manual birds COULD be ordered. why this is so is one of pmds minor little mysteries….
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Content last modified: January 24, 2014 at 10:28 pm
Q: Firebird 400 Radiator Outlet Size for 1968
I’m trying to figure out if the radiator in my 1968 Firebird 400 is original or not.
A: For starters, does your radiator have “HARRISON” embossed on the tanks ?
How about the Production Usage Code Tag ? 400 Codes…. UQ, UP
My original (UQ…RAI, 4spd) is in storage however, the “UP” tank I have is…
Upper: 1.5625″ Lower: 1.875″
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Content last modified: January 15, 2014 at 8:48 pm
Q: How Hot is Too Hot
One Question to all – What is hot (in your own opinion) for an engine to run? How hot – is to hot? 190?,195?, 200?,215?, 225?
A: In my opinion, 215 is when you start looking at the guage more thn the road. 225 is when I shut it down before it gets worst. 235+ and you’re in dangerous territory. 250+ things start warping and cracking.
Octane doesn’t directly affect your temps, however, if you car pings because of low octane than this can make it run hotter because you’re not running at an optimum condition so the engine has to work harder to produce the same power (and I’m sure that pre-ignition might generate more useless heat).
Get a desert cooler, a 160 thermostat, a good engine flush, a decent water pump, run a 50/50 mix (Destilled water is preferable. More water than collant is actually better for temps), run a little on the rich side, use the 400/AC car filler pannels, and everything should be ok. Almost forgot, the fan shroud itself is another important item – don’t know how many cars seem to come up short on that one.
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Content last modified: January 15, 2014 at 8:49 pm
Reference:
- 1968 Dealer Service Information Bulletin 68-I-68
- 1967 Dealer Technical Bulletin 67-T-13
Q: Overheating Engine
I just recently purchased a 1967 bird with a 400 and an automatic tranny. It needs some work but for the most part is all original. The motor has 670 heads and is a YT.
It seems to over heat when sitting still. When I am driving it runs about 180 but if I sit still very long it heats up rather quick. I replaced the water pump and put a 165 thermo in it. The radiator seems to be circulating any suggestions?
A: The overheating could be several things: Poor or no coolant, Improper coolant level/mix, bad fan clutch (check hot w/ engin off. If it spins freely, it’s bad), bad fan (if it has a cheep after market flex fan these blades get weak), missing fan shroud, partially clogged radiator (have flushed), bad water pump (possibly a broken impeller. check last) . If it has A/C it could have a bunch of junk between the condenser and radiator (this happened to me on a Corvette).
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Content last modified: January 15, 2014 at 8:50 pm
Q: Overheating Engine (Revisited 2)
Been playing with my 1969 with a new 455 (1000 miles) that doesn’t seem to have the correct power it should or maybe I got sold a lousy cam with the rebuild. Here’s part of what’s going on, any ideas out there?
Ran the car a little on Saturday. with an HEI and timing set at 12degress with vacuum module attached to vacuum source high on quadrajet body it will overheat at idle. Lowest idle I can achieve is 800 RPM. Running at street speeds keeps the temp down.
I have put new non-flex fan in, new radiator rot out, new water pump and thermostat at rebuild. and have had this problem since the motor was built. (shop has gone out of business, surprise!) Still runs slow, but has decent power, about equal to the 350, 2-bbl that was stock in it before. Could the cam be causing the overheating? or maybe there is something obstructing water flow internally? It still does not seem to run right.
When I started it up, it ran at high idle for over 5 minutes, choke was off, nothing would bring it down and then all of a sudden it just dropped down to 800RPM, maybe it needed to overheat to plug up some vacuum leak somewhere? Any ideas?
A: Do you have a fan shroud on it??? If not, then there is your problem since when the car is not in motion, it requires the shroud to assist the fan in sucking the cool air through the radiator.
One other thing you might try is retarding the timing. 12 degrees might be a little much.With vacuum advance, and mechanical advance, you might be actually running at well beyond 12 degrees at idle causing high heat.
A: First thing that comes to mind is the timing. If it is too retarded it will cause poor performance and overheating. I’m not sure whether the port that is “high on the quadrajet body” is ported or manifold vacuum, but if there is ANY vacuum advance at idle and you set the timing to 12 degrees, you’re timing is FAR too retarded. Disconnect the vacuum line from the carb and plug it. Just to be sure, also cap the inlet to the vacuum advance. Then set your initial timing to 12 degrees and see what happens. Might just solve both problems.
A: Did you add a full shroud? And what is the clearance between the fan blades and the shroud? Also, is the fan positioned in the rear of the shroud, inside the shroud, or is it just inside the rear of it? These factors are very important to provide good cooling suction. I ran my 1968 with no shroud, too small a fan for my shroud, and also improperly positioned and they all greatly affected the temperature of my engine at idle. I now have the original fan, with the original shroud, and with the fan spaced just inside the rear opening.
Take a look-see. If any of the ideas I mentioned are as you currently have it, try correcting it. It made a big difference with mine. Good luck.
What I mentioned about the timing is that if you have the dist too much advanced or too much retarded, that will also affect the temp. To time it, disconnect and block your vacuum source, and time the car, preferably at idle depending upon what your cam calls for, and yoru compression, I would think you should run at no more than 8 degrees but no less than 4. Remember, an increase in timing before TDC, such as going to 12 from 8, is Advancing it. Too much advance will create more heat, and if you’re really unlucky, detonation.
A: I’m going to ask a very silly (but obvious) question:
Are you running with a reasonable compression ratio for the fuel that you are using? I.E., 9-9.5:1 for 93-4 octane? The reason I ask is that it is possible that that 455 was fitted with smaller chambered heads off a 400 or 350. Any shop worth it’s salt would never have done this, but I think it happens. You should not run head chambers less than about 95 cc’s on a 455. Some 400 heads are OK, but the ones off higher compression engines will result in even higher CR on a 455. Higher compression with inadequate octane rating will result in overheating at idle and detonation under load at standard timing settings. (Not to mention broken pistons, rings, etc. Sometimes guys try to “de-tune” the ignition to get rid of the detonation, but end up losing a lot of power. (Been there, done that) Your CR must match the fuel rating or you are going to have problems. Get the head code off the center exhaust ports and make sure they are OK for a 455. Other than this, you been given some pretty good advice from others on the list…….
If I’m being too presumptuous, I appologize, but I ended up with engine damage and wished someone had told me so that I wouldn’t have to find out the hard (expensive) way.
A: I was reading the street machine articles written by Jim Hand and I came across something that jogged my memory. He warns about harmonic ballancer outer ring migration, which usually will throw your timing mark off into the retard region. This will result in heating problems and lost power. I had to replace a ballancer a few years ago because it didn’t line up with my timing pointer @ TDC. (I had just finished checking my cam timing with a degree wheel and had slipped the ballancer on @ TDC to check it). I had just never corrolated this to any previous problems. It is certainly worth looking at….. we usually take that little groove on the ballancer for granted when timing the ignition.
A: I have a ’72 455 in my 1968 and had a similar high heat problem. Apparently the crank pulley was much a much larger diameter than one that would be found on a 400. This was causing the water pump to spin faster than normal. At idle, the coolant was moving through the radiator too fast to be cooled very much. When driving, and with good air-flow through the radiator, the temp would return to normal. I put on a smaller crank pulley and the problem went away. And be aware that not all flex fans are the same. Some really suck.
A: Once again Ive been reading the FAQs and have come across a problem adressed that I encountered. The problem concerns a 1968 with a 455 and over heating.
I put a 455 in my 1967 and, of course, it ran hot. A friend did the same in his 1968 with the same results. Heres how we resolved the situation. I assume the waterpump thrustplate is not missing…Ive seen it frequently!!! First we made sure we had both the lower air baffle (below lower valence) and the two filler panels between the core support and the front bumper support. The filler panels were standard on 400s and on A/C equiped cars. The seal up the grill area and force the fan to pull air through the radiator instead of around it. This, for the most part solved the over heating at idle problem.
Both of use used 400 heads on our 455s and this contributed to the problem. After several broken pistons (we used early small chambered heads) we both switched to late model large chambered 400 heads. This, for the most part solved the problem, but we did end up installing heavy duty 4 row radiators…probably over kill, but then again summer in Florida can get things a bit warm.
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Content last modified: January 15, 2014 at 9:10 pm
Q: Overheating Problem (Revisited 3)
My Firebirdd is overheating and has low oil pressure. Is the low oil pressure causing my overheating problem.
A: I had problems with the cooling on my last 1968 after I rebuilt the engine. A few things to check
1.) Does the clutch fan actually work???? Mount a regular fan in its place to test to see if the engine now cools properly. I’ve never seen the clutch guts, but they can discontinue the correct lock-up and revolve at less than 100% of the correct idling speed. I have had this problem. It looks like the fan is working, but it is actually going much slower than it is supposed to, hense overheating.
2.) How long has your radiator been out of your car?? One of the oddities I have encountered is that when a radiator is romoved, crud (rust) that has circulated in dirty coolant will sometimes settle and clog the passages. Self flushing doesn’t seem to cure it, because it becomes hardened in the passages, just like a clogged drain in your house. It will need to be replaced, or removed and boiled by a pro radiator shop.
3.) You are running an anti-freeze/water mix aren’t you? Running 100% of either can be a problem.
4.) A recent article (either Old cars weekly / or classic auto restorer) discussed this topic in general. One of the often overlooked items is that engine blocks and head castings that sit for long periods of time without use had clogged coolant passages. Did either of yours sit without getting boiled out?
A: With regard to low oil pressure and overheating, that is a common problem. Here is the deal. Oil pressure is a measurement of resistance to flow (the flow of oil). The thinner the oil, the easier it flows. When your oil gets real hot, it flows very easy, hense the oil pressure drops. At start-up, the oil has a high viscosity (it’s thick), so there is plenty of oil pressure, but relatively low flow.
All automobile engines have a built in pressure relief valve, either in the pump or somewhere in the oiling system. In theory, you can never go above the max PSI as long as the pressure relief is working. The oil pressure will level off at high RPM because you have hit the limit of the pressure relief valve. At idle, the relief valve would only work when the oil is very thick, such as on a real cold day. It’s kind of weird that way. We often make the mistake of thinking that only oil pressure counts, but flow is just as important. That’s why most engine damage occurs at start up. There is very little or no flow for a few moments, even though the PSI jumps up instantly.
So, to answer your question. It is possible that your bearings are worn and the resistance to flow has been reduced from bearing clearances that are above the max tolerance. A pressure problem would normally show up first when the oil is hot and thin and at idle speed. It is also possible that your oil pump is worn and has reduced flow and that in turn is creating reduced pressure. When the oil is hot and therefore thin, the problems are likely to show up. But… my bet is simply that your car is running too hot. Get it to cool down and stay cool. Your oil pressure will likely rise to where it is supposed to be. Let the car idle, and watch what the oil pressure at about 195 degrees. Ideally, I would never want an older Pontiac engine to be above that temp. If the oil pressure at that temp is acceptable, then it’s just a matter of getting the engine to cool down to that level or lower. Beyond that simple diagnosis, we are talking removing the oil pan and checking the oil pump, bearings, etc. Not easy….
One last point. Are you running headers????? They aren’t causing the oil pan (and the whole engine compartment) to get hot are they? That situation will certainly cause thin oil (low PSI) and engine overheating. Headers are a real pain in a Firebird. No room to dissipate heat in the engine compartment! And…..by all means… check the other E-Mails and pay attention to the one on timing problems related to overheating. Solid advice!
A: First lets assume that the system is full of a coolant at the proper mixture and that a new and correct pressure radiator cap is in place. I also assume that the coolant was topped of after the engine ran and the thermostat opened.
What type of fan do you have?. If it is a clutch fan, is the clutch part still working? Are you using a radiator shroud? Is the fan set at a proper depth within the shroud? Are the original baffles in place on top of and underneath the core support? Do you have anything blocking the airflow in front of the radiator? Is it the proper radiator for the car(Not intended for a 6 cyl is it?). Have you had the system flushed to remove deposits/corrosion? Is the lower radiator hose collapsing when it gets hot? Do you have one with a spring in it?
If you are moving too much fluid with a higher volume pump there might not be sufficient time to absorb the heat. Retarded timing could cause it to run hot. Lean carb also. Has the engine been rebuilt recently? A tight engine may run a little hotter. Is there a possibility of air in the system casing cavitation/steam pockets? Is the thermostat working? Is the water pump impeller exactly the same size/shape as an original one? Is it possible that the water pump shaft is slipping and not turning the impeller at the intended speed?
Red-Line makes a product called water wetter that is supposed to reduce water temperature. I believe that it reduces the surface tension of the water allowing more of it to contact the metal surfaces. I think they claim about a 10 -20 degree F drop (bought mine at a auto part store). I think it helped, but can’t remember how much. It is about $7 US. (clear bottle pinkish-red fluid).
Have you tried an external oil cooler?
Has it ever run at the proper temperature? If so what have you done to it since then?
A: Back to a few basics….. What happens when the temp in your car rises???
Crap happens:
Compression maxes because the rings seal really, really tight. Try disconnecting everything (electrically from ignition circuit) and crank your engine over by hand, you’ll see the difference in resistance. Of course, you can also test this with a compression tester. Bottom line, the engine is tough to turn over.
Okay, we all know the obvious, the starter is at max stress because high temp causes high resistance in the electrical windings / armature, meaning less than ideal starting.
When the engine turns over (barely) preignition occurs and it says No go! No go!
So…. What is the answer? Don’t even think of fixing it with a starter solution. There is only one real answer…. Get the temp down…..
You can diagnose until you are ready to puke, but here are some steps I take to ensure I’m going in the right direction. From the cheapest to most expensive solution.
1.) You are running 10W40 oil. A grade of 10W30 or less will aid in the rise in engine temp.
2.) Run a blend of anti-freeze and water per the coolant mfg recommended mix
3.) Be sure to run a thermostat (don’t run without it or the coolant will not have time to cool properly).
4.) Your timing is correct isn’t it? To much timing will making it overheat faster than you can say boilermaker. I also include correct point gap in that discussion.
5.) Your radiator isn’t even slightly plugged is it???? These are 30 year old cars. If your radiator is more than 10 years old, chances are some of the cooling rows are plugged. Have it professionally rodded out. Home mechanic cleaning materials are a joke on a radiator this old. Oh and if the radiator was removed an let to sit long enough for the sludge crud to become hardened in it, you are in for a super plug job.
6.) Your fan shroud is installed properly isn’t it??? I won’t say any more on this one.
7.) Get rid of your headers!!! Oh no… the evil of such discussion. Headers in most birds cause a problem with oil temp rise and underhood head (causing coolant temp rise). They are too close to all of the mechanicals and the starter in a bird. I have installed and removed them in several birds. That step alone can solve the problem. Consider using the HI perf manifolds for 68.
8.) If you must run headers, install an oil cooler and 4 row radiator. That will help. It may or may not solve it.
9.) Your engine isn’t worn to the point where the bearings are bad, or it has a bad oil pump, is it??? In either case, you will suffer reduced oil pressure and the problem compounds the longer the engine runs. The engine will begin to overhead from additional friction caused by reduced oil pressure. The hotter the engine, the thinner the oil gets, making flow easier and pressure worse. The only solution is to replace the problem components in your engine.
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Content last modified: January 15, 2014 at 8:54 pm
Q: Overheating Engine (Part 4)
Does anyone have any suggestions for an overheating engine? I have an overheating problem with my 1968 400. When idling it’s fine. Sits right about 180-190. As soon as the car starts to move it gets hot quickly. If I stop for a light or a stop sign it immediately drops back to 180 or so. The radiator has been cored. I’ve replaced the thermostat and the fan clutch. Any other suggestions?
A: The one thing I found out was, although my radiator looked good, it was about 30% clogged. I was using a stock clutch fan and shroud. After my radiator man cleaned it out, it would idle all day long without overheating.
A: You know I was thinking the same. My 1968 400 didnt overheat during its life here in Orlando,but it was in good mechanical shape. Even with the a/c on it didnt go above 220 if idled all day.
Heres a check list.
-
water pump make sure its the proper cast iron impeller
-
thermostat 180 F is fine 160 will work too,dont leave this out
-
check timing cover and waterpump baffles these must be in good order without pinholes,if not buy the stainless replacement.
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check static timing and advance on distributor must be right on or motor WILL overheat
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engine condition, clogged cooling passages will ruin a motor
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heater core still intact and flowing good
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radiator still flows fine no bent fins and mud inbetween fins,no loose fins
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hoses must be fresh and wire installed in lower one
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fan pulley and fan,proper one as factory installed,no gimic ones here.
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a/c cars (not Brads) had smaller pulleys to speed up the air /water flow
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proper fan shroud(OHC-6 didnt use one only a finger guard)
this check list will if followed lead to a happy and cooler car. The only exception to needing auxiliary fans is large cammed ultra hi compression,ultra low gears,hi stall speed converters.A stock motor if in good condition shouldnt overheat.
A: Take a look at your lower radiator hose, squeeze it. Does it have a metal spring inside of it? If you can squeeze it flat then chances are you don’t have a spring. The lower radiator hose is the suction side and when you rev the car up with no spring in the bottom hose then alot of times it sucks the hose closed. Like when you put your finger on the end of a straw and suck on the other end it flattens in the middle and that sounds like what could be going on. Also with the car idling put your hand if front of the air breather and feel the flow of air, now have someone in the car rev it up to about 2,500 rpm and see if there is a great big boost in the amount of airflow, sometimes a new clutch doesn’t necessarily mean a good one. With the type problem you have I would say it has something to do with rpms which is generally the fan clutch or the lower radiator hose.
A: My view is that a great many overheating problems are related to wrong timing or carb set too lean. Many of us are spending big money on fancy water pumps and big radiators when we really need to sort out the basics first.
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Content last modified: January 15, 2014 at 8:56 pm
Q: Overheating Engine (Part 5)
I have tried everything suggest but I just can not find the problem to my overheating problem. I am about ready to give up and move north. Any ideas?
A: One guy on the post (forgot name) may have been close when he suggested that over heating in the first gen birds was due to the design of the cars front end. An old time radiator man I often go to said that the firebird radiators are the smallest ones Pontiac has ever put in cars and expected them to do so much ie. cool big V8s.
This guy also had an excellent tip for a mysterious overheating problem. All you overheaters may be over looking the old head gasket leak.
A head gasket can develop a small leak near a water jacket. The problem may not effect the performance of the car and often is undetectable until the overheating starts. When the leak in the gasket develops between the combustion chamber and the water jacket, a small amount of compressed air is forced into the coolant while the engine is running. The results are large pockets of air forming where the water should be and turning to steam from the hot spots in the block. The results are overheating followed by blowoff over flow.
The check the old guy gave me goes like this: Disconnect the fan belts so the water pump will not turn. Disconnect the top radiator hose at the radiator and hold it up vertically while filling the radiator with water until you can see the water in the end of the hose you are holding. While everything is cold (engine, water) start the engine and watch the water in the end of the hose for small bubbles. They will appear before the hose gets to hot to hold and the indecate a bad head gasket.
This whole deal works. I used it on my 1969 and found the cracked gasket…Old radiator Bill impressed me on another occasion when I plopped down a radiator in his shop and he eyeballed it for a few seconds and proclaimed, ” that’s from a 1967 GTO!
Good luck with the heat
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Content last modified: January 15, 2014 at 8:57 pm
Q: Water Pump for 1969
Were there two variations of the 1969 Water Pumps?
A: There are two pumps for a 1969 Firebird. I seen them listed as earl and late 1969 (The early pump was the short one).
3 31/32″ Hub Part#9797581 Cast number 9796351
There is also
4 15/32″ hub
You can also tell just buy looking at the water pump pulley. I’ve observed that the a/c equipped cars had the longer pump also.
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Content last modified: January 15, 2014 at 8:58 pm
Q: RPM and Temp
I’ve got a 1968 Firebird, built 350, 3:73 rear end and a 3 speed AT. When I’m on the interstate, what is a reasonable rpm to be at (ie., what is too high). Also, I think my thermostat is blown, the engine is a 73 Pontiac, what is a good temp?
A: The higher RMP your engine runs, the greater the wear, especially for sustained periods. Not to mention the penalty in fuel economy. I’d try to keep the RPMs below 3300 or 3500 for highway cruising speeds. Depend- ing on tire size, that might be 55 or 60 MPH?
You can try a taller tire, change the rear ratio, or get an overdrivetransmission.
Regarding the temp question, I feel that 180 to 205 is within a normal range, depending on load, speed, and air temp. Even 210 is OK if climbing a steep grade on a hot day, or sitting in traffic in August. Modern cars are designed to keep pretty close to 200 for max. efficiency. A frozen thermostat in the open position will not allow the car to warm up, or be slow to warm up, and will result in premature wear in the cylinders. Heat is required for good operation, but not too much heat. Frozen shut will cause overheating pretty quick. I run a 160 or 180 degree thermostat in the summer, and a 190 in winter.
If you are relying on the factory temperature gauge to determine operat- ing temps, be warned that they were never too accurate when new, and with age, they are completely suspect. Add an aftermarket guage, even if only temporary, to determine how hot you’re engine is getting. Mech- anical guages are more accurate than electrical.
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Content last modified: January 15, 2014 at 9:01 pm
Q: Heater Core Replacement (Non-A/C)
I need to replace my heater core. The service manual is not to much help. How should I go about it? How tough is it:? should I forget it and just drive when its warm?
A: It’s a tough job. Even tougher if your car has factory A/C. The core is fastened inside the air box behind the glove box. If the car doesn’t have A/C, I think you can get to all the bolts without removing the passenger side fender well. The control cables are easy to remove and replace. While you have the heater box out, it’s a good time to clean it up and freshen it up with a new coat of semi-flat black.
If your car has factory A/C, drop me a line off-list and I’ll try to help you through the details.
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Content last modified: January 15, 2014 at 9:02 pm
Q: Emissions Decal Placement
I am looking for the proper place to put the black emissions decal. I think it goes on the bumber filler panel, althought not sure if it is the passengers side or drivers side.
A: I measured mine. It is on the passenger-side filler panel. It is positioned 4 1/2″ from the outside edge and 1 1/2″ up from the bottom edge.
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Content last modified: January 15, 2014 at 9:30 pm
Q: Throttle Problem
I recently purchased a 1968 Firebird 400. The car seemed to be a dog compared to the other 1968 Firebirds and GTOs I have owned in the past. After doing all the usual tune up tricks I noticed that my accelerator pedal only throws the throttle open half way before hitting the carpet!
I looked for an adjustment to compensate for the restricted pedal movement or a way to remove the carpet but neither seemed to have an obvious answer. Has anyone else experienced this?
A: If the carb has ever had really strong spring installed, it very well could have bent the inside linkage. My GTO had this happen. I bent it back and welded on a brace so it wouldn’t happen again. Also, didn’t the Firebirds 400’s have some sort of throttle stop to keep from getting full throttle in order to “lower” the horsepower. That might be when the linkage got bent originally. Someone tried to stomp the pedal to the floor, it hit up against the throttle stop and bent the inside linkage. Just a theory.
A: After a closer look I discovered that the reason my accelerator pedal was only throwing the carb half open was that the mounting bracket for the pedal was cracked in two.
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Content last modified: January 15, 2014 at 9:42 pm
Q: Timing Adjustments
I am having a problem setting my timing on my car to the indicated specifications. What do I need to do to fix the knocking on my HO engine?
A: I’ve never had that much of a problem with the timing on my 400. But I don’t pay that close attention to the timing at idle. For mechanical advance (with the vacuum advance hose to the distributer removed and plugged), I set the timing at 32 degrees BTDC at about 2600 RPM (you’ll need some timing tape for this). Once you set the mechanical advance, disconnect the vacuum advance hose at the carburator end and hook up a vacuum gauge to the carb that you can put inside the car. Then go out for a little run and write down the maximum vacuum when running at a constant speed with the engine at 2500, 3000, 3500, and 4000 RPM (make sure the road is somewhat flat). Go back and hook up your timing light again, set the engine speed at about 2600 RPM, connect a vacuum pump to the vacuum advance and pump it up to the your max vacuum reading you read in the car. Your total advance should be 50 degrees at this point (that’s what I set mine too, I know people that go higher, but not much). If you have a distributor with adjustable vacuum advance you can adjust it until you get 50 degrees. If your motor is spark knocking you’ll have to back off on the timing until it doesn’t. But that ussually means there is something else wrong, like your vacuum advance is advancing your timing too much, you’re running too lean a fuel mixture at max advance, or you’re running to high of a compression ratio for the fuel you’re using. I think most people run to high compression for street gas. I don’t think you should run more than 9.5:1 on plain old 93 octane. And most people with older cars have compression ratios over 10:1………………………………….spark knock city……………… If the production timing marks weren’t cast right into the timing chain cover, I would have taken them off a long time ago. Timing tape is pretty cheap and alot more accurate. That’s my 2 cents worth anyway.
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Content last modified: January 15, 2014 at 9:46 pm
Q: Timing Adjustments (Revisited)
A while ago there were a few of you who said that after they set their timing, that a timing light showed it to be WAY advanced, like 20-30 degrees. I think I asked once before but I’ll try again. If you’re not setting it with a timing light in the first place, what are you setting it with?
A: I originally asked this timing question. I set the timing by ear and feel. I loosen the distributor and advance it until the engine starts to miss, then back the timing off a little. Then I rev the engine and see to see if it pings. If it does ping, I retarding the timing a little rev the engine again. I keep doing this until the pinging is gone or very, very minimal.
All the mechanics I know never use a timing light and use this method.
A: The only problem I have ever had with using that method is that with the timing set to run it’s best at 700 or 800 RPM, often it will have too much initial timing to start easily. What I try to do is set the initial by what will start easily (as much as it will take w/out trouble) then adjust the weights and springs to get the total advance I need, and have it start coming in fairly early, like 700 or 800 RPM. It’s a lot of trial and error work, but it has always worked well for me. Then once I have it right I check it with a light and write it down so that I can put it back next time I have the distributor out.
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Content last modified: January 15, 2014 at 9:49 pm
Q: Timing Adjustment to Fix Overheating Problems
What are the steps in adjusting my timing to fix the overheating problem.
A: Here’s the deal on timing, back to basics.
First, disconnect and block off your vacuum source to the vacuum advance. Its ONLY purpose is to increase gas milage. Next, if you keep your engine at or below 800 RPM you will have no mechanical advance. So now the only timing is due to INITIAL timing. Let’s say you set the spark right at TDC, the flame takes so time to form at “explode” so the force of the explosion happens AFTER TDC, piston is already on its way down, you don’t get much power. So you ADVANCE the timing to whatever gives you the best performance, which is usually between 7-12 degrees BTDC. If you have too much timing and the spark happens too far before the piston reaches TDC, then the force is pushing against the direction the piston is moving and you get detonation or knock. This is BAAAAAD.
As your engine RPM’s increase, the amount of TIME it takes for the engine to turn say 30 degrees is much faster than at idle, but the TIME is take the flame to burst hasn’t changed. So the timing is increased further by the MECHANICAL advance. Usually adding up to 20-25 degrees of advance to the INTIAL timing, for a TOTAL timing of 32-38 degrees.
Finally, vacuum advance was added for the purpose of further increasing timing at cruise. Most times it is connected to a ported vacuum sorce. This source has NO vacuum at idle, the most slightly off idle and then decreases to zero again at Wide Open Trottle (WOT). When cruising you can add an additional 15 degrees or more of vacuum advance, bringing your timing up to 55-60 degrees BTDC. This is the one to be careful of, too much and you can get detonation. Always stick to the low side to avoid detonation. Remember, it’s just for gas milage.
One more thing to touch on. Manifold vacuum is maximum AT IDLE. All other times it acts just like Ported. If you hook your vacuum advance to manifold vacuum you will have 8-12 intial plus 15 or so vacuum for 23-27 degrees BTDC of timing AT IDLE. This will affect temp, though I’m not sure which way. I DO know, that most 1st gen birds came with a TEMP activated switch which actually switched the vacuum advance soure depending on the engine temp in order to keep it cool! The was specifically for long periods at idle.
Now, lets say your car is set up this way but you SET the timing to 12 degrees WITH the vacuum advance hooked up to manifold vacuum. That vacuum advance can is giving you 15 degrees or more of advance. That would mean your REAL INTIAL timing (without the vacuum advance) would be 3 degrees AFTER TDC, which is way to far retarded.
Bottom line, turn off the vacuum advance until you figure out the heating problem. Its ONLY purpose is to improve gas milage. Set the INITIAL timing to 8-14 degrees. See if that helps.
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Content last modified: January 15, 2014 at 9:50 pm
Q: Sport Option
I have seen the 400 engine refered to as the “400 Sport Option” in a couple references and the 400 front bumper emblem drawing. Was this only for the 400?
A: Actually, the “sport” reference was not the actual designation for the 400 option. I did this sketch quite awhile ago and probably borrowed “sport” from some reference in a magazine and/or older GM Parts Catalog. I do believe in some factory literature (Parts Books?) there was/is a reference to this option as the “400 Sport Option”. Then again, I could be wrong. Either way, the point here is that the “400” option consisted not only of a 400 engine but appearance items as well…. Chrome Grill Moldings, Frt. Bumper ‘Crest’ Emblem, “400” emblems on the Hood and Deck-Lid, Redline Tires, Chrome Engine Trim, Dual Exhaust, 4Bbl Carb, firmer shocks/springs.
A: You are correct in the reference to a “400 Sport Option”. It is mentioned thruout the parts catalog and even in the accessory catalog.
However in the accessory groups is a separate heading of “SPORT OPTIONS” which includes all Tempest Sprints, Firebird Sprints,Firebird 350,Firebird HO(350)and Firebird 400. Since the engine options are also listed in a separate category it excludes all of the Firebird models listed above.The only engine option that is listed for Firebird is the 400 HO. What this would lead one to believe is that all of the 5 specific models of Firebird except the base 1 bbl OHC-6 were considered to be “Sport Options”. I think this was abbreviated to eliminate confusion to include only the “400” option.
A: The sport option was referenced in the 1968 Pontiac Sales Manual used in each showroom: 1968 Pontiac Sales Manual – Sales Price Index
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Content last modified: October 26, 2019 at 7:19 am
Q: Engine That Sat for 5 Years
What is the precedure for an engine that was rebuilt and then left sitting five years with no break in period?? It was only started at the rebuilders shop and i need to know what steps I should take to get it loosened up and ready to run. I know that the fuel system needs to be cleaned and carberator rebuilt.
A: My procedure is as follows:
– Remove all the spark plugs
– Using a piece of tubing on the end of a oil pump can, get 2-3 squirts of HD 30 motor oil into each cylinder -With the spark plugs out, crank the motor and watch the oil pressure gauge. It should start to register SOME oil pressure. Do this 2-3 times, not cranking for more than a minute and allowing at least five minutes between each sequence to allow the starter to cool. If you don’t have a pressure gauge, remove the valve cover and make sure oil starts to flow out of the rocker arms.
– Once you are sure that oil is flowing, re-install your plugs and wires.
– If your distributor was installed correctly and your points are good, the motor should fire and run.
– While running, listen for any lifter noise. The rocker arm clacking should begin to quiet down as the motor comes up to temperature and the lifters pump up.
– If everything goes well, all your should have to do is the final timing and dwell settings.
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Content last modified: January 16, 2014 at 7:00 am
Q: Vin, Body Tag, and Engine Code Information
Running the vin number and body tag number on oakmediacreations firebird page the production numbers of the vehicle didn’t match one another plus what do the codes on the engine stand for:
Block Casting numbers on R/F of engine (only numbers I can see)
GM4
Stamped numbers on the right front of engine block
508743
YJ
A: This is correct, these two numbers found on the body tag and the VIN will not match. The numbers on the VIN represent the Sequential Production Number. The numbers on the Body Tag represent the Unit Number or consecutive build number. The last tells in sequence when the car came off the assembly line. Again, the body tag number will not match the actual sequential VIN number.
Block Casting numbers on R/F of engine (only numbers I can see) GM4
I do not know what these represented on the block.
Stamped numbers on the right front of engine block
508743 = Motor Unit Number
YJ = 8 cyl, 326 cid, 250 hp, 9.2:1 comp. ratio, 2 bc carb, auto trans.
Sources: Firebird Red Book, Catalog of Firebird ID Numbers 1967-93, Pontiac Historic Services, Year One Catalog
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Content last modified: January 24, 2014 at 9:53 pm
Q: Removing Engine
I now have a question. Am I going to be able to pull the motor without also removing the trans or should I remove the motor and the trans toghether? Or, better yet, what is the easiest way to get the motor out? Now please remember, I am a rookie at this. This will be my first engine removal.
A: In my opinion it’s easier to remove the motor with the trans all at once. Just remove the trans cross member, radiator and the distributor and you’ll be ok. The fan makes it kinda tight but it should come out without taking it off.
NOTE: Make sure that you mark the position of the rotor when removing the distributor and make sure that you don’t turn the engine after you’ve removed it. If you do turn it then you will have to find TDC on cyl. #1 and set the distributor to that. Just put the distributor back in after removing the engine if possible.
I used one of those plates that bolts up to the intake manifold and used the rear lifting hole with the cherry picker. You may want to use one of those lifting bars that has a handle and allows you to shift the center of the lift. The only issue is that you need to use chains bolted to the front and rear of the engine for that (no biggie but ….).
Put blankets or other things on your fenders to protect them from getting scratched or bangged up.
A: I pulled mine in one piece – engine and tranny. But I did have the front end off of mine. I would recommend removing it anyway, if you’re doing compartment detailing. It comes off in about an hour. Unplug the lights, remove the radiator-to-fender gussets, unbolt the hood latch-to-radiator, four bumper support bolts and it comes off in one big piece. The core support is held in by four bolts.
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Content last modified: January 16, 2014 at 7:02 am
Q: 400 Rebuild Suggestions
i have 1968 firebird i restored last year. I’m get ready to rebuild my 400 and looking tricks and tips for a pontiac motor. can you help me
A: The following is some helpful information on properly building a street strip Pontiac 400. If built properly, the engine will make 450+ HP with commonly available parts.
BLOCK:
Start by boring the block .060 to get max cubes (413), hone to a #625 Sunnen finish with .003 piston clearance and minimum deck it. Leave, or add the scallops at the intake valve side of the bore to unshroud the valve. Make sure the main bearing saddle alignment is + -.001 or better. A 2 bolt block is ok providing you use studs. Remove *all* the casting flash in the lifter valley and re-tap/deburr the whole block. Don’t forget to tap the oil galleries for threaded plugs, drill an .042 hole in the right rear plug for dist gear cooling and chamfer the oil filter block and oil pump holes nice and big. Take your rotary file and elongate the oil return hole in the front of the block down to the valley floor for immediate drainage to the pan, there are others along the sides between the lifters if you feel energetic. Do *not* scrimp and try to save money on the block! You get what you pay for so use a competent machine shop!
When cleaning your freshly-machined block for assembly use *hot* water and dish soap, a *steel* rifle-cleaning rod will work great for the oil passages, a 12 ga. shotgun brush for the lifter galleries and a 9mm for all others. After cleaning soak the block with WD-40, wipe the cylinders, you will see more blackness on you *paper towls*, clean again with soap and hot water using a pressure nozzle. If you have an air compressor blow dry the block and coat the cylinders immediately with oil.
CRANK:
Get an early 350 crank, have it magnafluxed for cracks, heat treated (case hardened), shot-peened and straightened. Grind it -.010 on the mains, offset grind the rod journals .015 (more stroke), you’ll need to go -.020 undersize to get the offset. Cross-drill the crank and lightly chamfer the rod oil-holes, chamfer the main oil-holes in a tear-drop shape in the direction of rotation, just a small chamfer will do. Micro polish it, since it is heat-treated it will polish nicely. Run .002 clearance on the mains.
The reason for using the 350 crank is that it is lighter and has thinner crank throws. You can also use a late 400 crank as it is a similar casting. Avoid very late 400 cranks as they have a different flange. The lighter crank will reduce your rotating weight and rev faster under load. If you anticipate super-high rpm, you may want to “knife-edge” the crank for even less weight and less resistance.
Before installing the crank clean it just as you did the block, they are covered with powdered metal after grinding.
***To use this crank you must also do the following:
PISTONS:
This is an area that I will hold back on the tricks slightly. If you *must* know more, private e-mail will do.
You will have to reduce the weight of the *forged* 400 pistons, you can machine some off the back-side of the dome, or machine or drill holes in the pin boss area from the bottom. Another way is to use thin walled tool steel pins, they are fairly inexpensive. Use moly-filled rings *only* with the Sunnen #625 finish. Ring end-gap is .014 top and 018 2nd.
RODS:
You *must* upgrade your rods to at least the ’73-’74 SD or preferably Carrillo or any other reputable racing rod as you will be revving this thing to 7000+ rpm easily. If you use factory rods you will have to remove most of the small-end pad to get it light enough to balance correctly with the 350 crank. Run .002-.0025 clearance. If you can afford it, use racing bearings. Grooved uppers on the crank. Torque rods by stretch to +.005 to .008.
OIL PUMP:
Use a Milodon 455 H.O. pump and tack-weld the pickup in place. I suggest removing the cover-plate phillips srews, loctite them and use an impact-driver to re-install them.
WINDAGE TRAY:
The stock ’65-’73 Pontiac 4/5 windage tray will work fine, if you can find a full-length one use it.
Take a cut-off disk and cut 2 square openings in the end troughs and 1 long slot in the bottom-center trough of the tray. Note the position of the end-pairs of rods above the tray, cut your square end-slots exactly below them. The two end slots should measure about 2.5″ x 2.5″ and the center slot 2.5″ x approx. 8″. When you make your end cuts on each slot, continue 1/4″ past the side cuts, this will allow you to bend a flange downward along both sides. You can set the tray on the edge of something and tap the flange down with a hammer, the metal is very soft so it bends easily. Find a piece of course perforated or expanded metal, cut it to size and form the same radius as the tray. Tack weld the 3 pieces in between the flanges and on the ends.
This modification will allow oil escaping from the crank to be blown directly into the pan and keep oil from splashing up onto the spinning crank, its good for 10-15 hp.
CAM:
Call Bob Cook at Competition Cams and go over your proposed setup with him, he is very experienced with Pontiacs and helps many a racer with the proper cam, etc. He is *realistic* so be prepared, he won’t let you over-cam your engine, no matter how nasty you want it. His # is; 800 999-0853.
HEADS:
Any big valve, early Pontiac head will work as long as it has 2.11″ int and 1.77″ ex valves and screwed-in rocker studs. Exceptional D-port heads would be 16, 12, 13, 62 and 48. The 62’s and 16’s should be fairly easy to find. These heads have 72cc chambers and should yield a 9.7-10:1 compression ratio, which will allow you to run a fairly radical cam effectively.
Heads, more than anything are an area that will determine how much hp your engine makes. If your cores are rusty, remove the freeze-plugs and have them acid-dipped. Start by installing new bronze guides and hardened exhaust valve seats for use with unleaded gas. Since the seats will have to be blended into the port, now is a good time to do some porting.
On a street engine do *not* fully port the heads! You want some turbulence in the port to keep the fuel/air mixture atomized, thus keeping your engine from loading up. The best street port-job that will wake-up your Pontiac is simply to open up the “bowl” area under the valve and blend back into the port-runner. Try and keep each port relatively close in volume, don’t get carried away removing material! Just blend the seat into the bowl/runner and polish. Use some “Dykem” machinist’s dye, or if not available use spray paint around the intake ports, install an intake gasket and snap the plastic locators in place. Scribe a line on the head where the ports are mis-matched and open them up with a *large-diameter* rotary file and blend 3/4″-1″ into the port. Leave the gasket on during this procedure (taped down and numbered) to insure a perfect match.
Minimum mill the heads if necessary and do a good multi-angle valve job. The spring umbrellas can be discarded, make sure you use spring dampners to reduce friction and heat build-up in them. If possible find a 1 piece intake valve for peace of mind, at present I’m not aware of anyone making a 1 piece exhaust valve for a Pontiac.
A good valve cover to use is a late baffled cover. You can spot them in the boneyard by the “8” dimpled spot welds on the surface. These covers have “fingers” that channel oil onto the rocker-balls. The next-best would be the bolt-on baffles that came on the 455 H.O. and the like. Poly-Locks would interfere with these however, you would have to use lock-nuts and hardened washers.
Do not use factory head gaskets, they are too thick and will add several cc’s to your chamber volume. Do use head studs if you can afford them, especially if you are planning to run nitrous.
INTAKE MANIFOLD:
Use a torker or preferably, a Doug Nash. I have a friend who has a couple of ’em, and a 750 Holley with what ever thickness carb-spacer your hood will allow. Third choice would be a gasket-matched early stock manifold with the #7 runner opened up to relieve the throttle bracket bolt-boss protruding into the port.
IGNITION:
Run an MSD #8563 distributor, 6AL box #6420, Blaster coil #8202 and Soft Touch Rev Control #8738 (or 2 Step Rev Control #8739). Use the biggest plug-wires you can find and stock heat-range AC plugs gapped at .035. Experiment with the plugs in each hole while the heads are off to get the electrode pointing down toward the piston on as many as possible. (or you can mark the plugs for later installation).
Timing curves vary with each application, a general rule is to keep it at 34-38 degrees total and don’t get wild on the street regardless of what you’ve read in the magazines. Getting it “all in” by 1800 rpm will only rattle and ping. Keep that figure at around 4000 rpm.
HEADERS:
If you can find a decent set of 4-tube headers that aren’t a nightmare to install and maintain use them. I recommend 3-tube “Tri-Y” headers because of their ease of installation and room, they will also make lots of torque at a very low rpm. Always use a cross-over tube on the way back to the mufflers and slightly smaller tube at the muffler exit.
FLYWHEEL and BALANCING:
If you run a 4-speed use a “neutral” aluminum flywheel and internally balance the engine. That will give you a softer launch without a lot of tire spin and will rev quicker.
The stock Pontiac dampner works fine, it is a waste of money to replace it, just make *sure* you torque it to 160 ft. lbs.
NITROUS:
It is better to build a “hot” engine and add mild nitrous, than to build a mediocre engine and cram it with the “happy juice” trying to make power. The result will surely be a pile of scrap iron, empty wallet and a severely bruised ego.
———
Well, these are the basics as I see it that will give you an 11 second car provided you have the chassis for it. If you run slicks, the right gears (4.33-4.88) and a race-prepared TH350 and have the Chassis extremely dialed in, I would put $$$ on a 10 sec run. 🙂
All this costs plenty of $$$, but take your time and shop prices, it will be worth it. This info is based on my many years of building Pontiac engines.
Happy Hunting!
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Content last modified: January 16, 2014 at 7:05 am
Q: Engine Rebuild
My new 1968 firebird 400 is burning oil on start up. I think I’ve got some time left before she’s real bad. So I’m starting my research now on rebuilding my motor. There’s several issues that have come up and I would like some clarification…If you can…
1) I have been told that a chevy engine will not fit the bell mountings and that the motor I most likely have…the original…is an oldsmobile engine…is that true?
2) I’d like to rebuild myself…I found pistons, valve rods in the yearone catologe…but no gaskets, rings. Is there a better engine rebuild source out there? Will a chevy rebuild kit work?
3) If I have cylinders reamed, will I need new pistons?
4) My chilton manual say there are oversized valves available for use in bored out valve guides. Is that true…where do I get em?
5) If I add high performance cam will I need different valves and valve rods and lifters?
6) If I change pistons to lightweight, and add a high performance cam is that still stock…you can’t see those items.
A: In short answer form:
1) True. Chevy uses a different bolt pattern for bell house mounting. The Pontiac uses what is called the BOP (Buick-Oldsmobile-Pontiace) bolt pattern, Cheby is …well, Chevy. The Pontiac 400 is Pontiac specific. Not the same as any other 400 by anyone. Only Pontiac parts fit.
2) See answer 1) Check PAW Atuparts Catalogue, Summitt Auto Parts.. Check into any hot rod type magazine to locate rebuild parts. Very common stuff..
3) If you “ream” The cylindes, I assume you mean reaming the ridge at the top of the cylinder. No new pistons are required. If, however, you mean to HONE or OVERBORE the cylinders, then new pistons are needed.
4) Maybe. It depends on the cam. Each cam manufacturer has recommendations. If you stay streetable, then stockers willprobably work fine. If you want something special,……. You have to pay to play.
5) Usually, stock means stock, from the factory. If you are referring to STOCK class at the dragstrip, the sponsoring raceing organization has a set of rules that define exactly what stock is. In NHRA stock class, some aftermarket cams are still considered stock. Lightweight pistons are usually not stock. If you are referring to street or bracket racing… Well what ever is under the hood is whatever you say is under the hood. Caveat Emptor! Let the Racer beware! *smiles*
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Content last modified: January 16, 2014 at 7:06 am
Q: Engine Rebuild (Revisited)
I’m looking for feedback/suggestions on rebuilding my 326 HO. I am restoring the car to as close to original as I can, but would like to get a few more horse power. I will be keeping the stock (points) ignition, headers are not an option, stock carter AFB 4bbl, stock intake. Given this, are there any suggestions on bore,cams, heads(port/polish), lifters ect… or should I stick with stock rebuild? would like part #’s and specs to give to machine shop. Is the extra $200 they want to balance it necessary? The shop says they will use a cadillac rear seal, will this work with no leaks? open to any ideas/critisizm.
A: As I’m sure most expert motor builders will tell you, the key to making good horsepower is to make the engine breath. Having said this and knowing your limitations on the stock exhaust and intake, there are still a couple of this you can do to give the car a little more zip…
1) Camshaft. This will be the least expensive purchase you’ll make. Mainly because your going to replace it anyway. I would look for a good grind that make most of it’s power at the lower rpms… say, idle to 4000. Since your motor will stat to choke down at the higher RPM due to your restrictions, a cam designed for higher RPMS will most likely reduce your engines performance. Also, consider matching the grind with the head characteristic (see #2)
2) Heads: here is where the power comes from. A mild pocket porting job on the intake bowls will help reduce the restrictions and help to obtain more flow or at least as much as the exhaust manifolds can handle.
Have the heads plained to obtain a 9.5 to 10:1 compression ratio (you may already be here since they are the original heads). This is kind of on the high side for cast heads and today’s pump gas but you will be OK with premium fuel as long as you don’t advance the timing too far (see 3).
Install hardened exhaust valve seats to reliably run unleaded gas.
3) Pistons: 0.030 over bore with flat tops. You’ll need to calculate the total volume of the cylinder and head chamber to obtain the proper compression ratio. Too much compression means you’ll have to use an av-gas or racing fuel blend to prevent detonation.
4) Block: decking the block is another way to increase the compression but may not be advisable with your current heads. I would figure out what the current compression ratio is and discuss this with a local motor builder (preferably one who builds racing motors) and then decide which way to go (decking the block vs plaining the heads).
5) Balancing: This is very gray area when considering your limitations. Balancing the components will help the motor to run smoother but at the lower RPMS the benefit are small. I would ask the mechanists to weight match the pistons and rods (use the heaviest piston on the lightest rod and vice-a-versa to get the best “overall” balance and let it go at that.
6) Cadillac Main Seal: I’ve never done it but it sounds like a great idea. There was a god article in the December 98 High Performance Pontiac magazine about this topic and I will try it on my next rebuild.
7) Engine Tuning: Once the motor is together, try experimenting with different jetting. You may be able to increase the jet size by a couple of notches because of the larger camshaft and better breathing heads.
8) Other stuff: There is literally no limit to what you can do to squeak out a few more horses: Hotter coil, performance points, low resistance spark plug wires, K&N air filter, high flow mufflers and exhaust, etc. Pick up a Summit or Jegs catalog and let your fingers do the walking.
If you want max HP and still have the stock look, consider having the intake and exhaust manifolds extrude honed. This is a process where they forcibly push an abrasive compound through the ports to open them up and remove restrictions. Kind of radicle but some of the limited late model racers use it to improve the flow on mandatary stock components.
Well enough from me. How about some additional tips (or rebuttals) from the rest of you guys???
A: Regarding tips for more horsepower, if youve got some money:
We went with a set of those aftermarket edelbrock heads for several reasons:
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from what I understand, a well ported set of stock pontiac heads will flow about 240 cfm, while the edelbrocks flowed close to 300 right out of the box. Ported, they flowed way over 300 cfm.
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Many pontiac heads flow well only to a certain level of lift, after which a larger lift cam does not help flow. The edelbrocks continued to see increases after .600 inches of lift, allowing a large roller cam.
With those things said, we had some problems all you considering this upgrade might want to hear:
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Our eldelbrock torkers ports did not match with the heads, and so the manifold had to be milled. (Strange since both were new and the heads were not shaved, and the parts were made by the same company.) Although the intake would have bolted on, we would have lost some power.
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since the edlebrock has the round port configuration on the exhaust, youll have to locate some factory style Ram Air IV manifolds or try to find some hedders (which is very hard) We had to settle for some hedders that were incompatible with air conditioning and power steering. We also had to cut a hole in the fender well to get one of the primaries that went outside of the frame to fit, as well as a little banging on the primaries.
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if you want to run more agressive than stock ratio rockers, the heads have to be modified for valvetrain clearance.
Although all this might sound daunting, the heads were well worth it, as we made 570 dynoed hp @ 5800 rpm, with lots of good old low end pontiac torque. (576 under 5000 rpm)
Finally, DO NOT run copper head gaskets with these heads, as they may leak. Our motor had to be torn down because it had water in the oil the first time we ran it on the dyno.
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Content last modified: January 16, 2014 at 7:07 am
Q: 350 Motor Mounts for 1969
A: Earlier I was asking about the Motor Mounts for a 1969 350, and I told you when I found out FOR SURE I’d give you an update.
The Anchor book is WRONG. The 1969 350 does NOT use two different mounts. They use the same mount on both sides and it is the SAME mount used for 400s. I believe it is Anchor PN 2254.
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Content last modified: January 16, 2014 at 7:08 am
Q: Motor Mounts Left vs. Right
There is a difference between left and right motor mounts. I don’t think that Ponchos used different mount for small or big block, but I know that Chevy does use different mounts for small and big block in the 1st gen. Cramo.
A: Whats a small block Pontiac??? An Iron Duke 2.5??? Sorry but it makes my skin crawl when i hear “small block Pontiac” All V-8 blocks were the same size from 55-79 there were a couple of variations like short deck 303,or low deck 301 but they all have the same basic block configration. Therefore there are no small block Pontiacs.
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Content last modified: January 16, 2014 at 7:10 am
Q: 455 Swap
I have an opportunity to buy a 455 out of a bonneville. Anybody know what (if any) modifications I will need to do to get it to fit?
A: This is a very simple swap. Since 1967, all Pontiac V8s have the same external dimensions, and will readily swap parts like intake manifolds, timing chains, and oil pans. The exception is the much maligned 301.
As another list member mentioned, the Feb. 2001 issue of Car Craft has a brief article on swapping a 326 for a 455. It contains some good photos of the differences between the 1969 and earlier motor mount bosses/holes and the 1970 and later version. There is also a good description of water pump and pulley issues that need to be addressed. The article would apply to those of you with 350s and 400s as well.
But, essentially, the easiest way to do the swap is to take the timing cover, water pump, pulleys, and accessory brackets off your present engine, and transfer these to the 455. The same applies to your exhaust manifolds. Now the 455 will just bolt into place like it grew there.
Some other issues not mentioned, or only lightly covered in the article are:
-Flywheel/flex plate. While the majority of Pontiacs in the late 60s and early 70s used the same sized crank shaft flange, the late 50s and later 70s car are different. In fact, there are up to 5 different diameters in the Pontiac engine family. So, measure the rear flange on your 455 and check to make sure that your original flywheel/flex plate will bolt on, or use the one that came with the 455 if possible.
– Manifold sealing. Intake ports on Pontiac heads changed roughly about 1972, so if this engine is later than that, you’ll need to get the correct gaskets to seal your intake manifold. In the Car Craft article, they used some thin metal to block off the heat passage crossover, which is the area that will most likely leak. This is assuming you will be using a 1972 or earlier intake manifold.
– Engine weight. While we don’t have any exact figures on engine weights, it is logical to assume that a 455 weighs more than a 326, perhaps. You may have to get new front springs for your car if once the bigger engine is in and your front suspension bottoms out.
– Water pump/pulleys/ accessory brackets/timing covers. Pontiac in it’s infinite wisdom, changed the design of these front engine dress parts several times, and mixing these parts leads to poor pulley alignment, thrown belts, and premature baldness. But to give them credit, the blocks themselves are pretty universal.
Whatever you do, use all the parts from either the donor Bonneville, or your present engine.
The 1967 and 1968 Pontiacs (as well as the earlier engines) used an 8 bolt timing cover and pump. In 1969, they went to an 11 bolt cover and pump, but had two different pump designs, each a different height. This means that the pulleys and brackets are different for each pump type. The 1967 and 1968 items have different part numbers also, and they may be incompatible as well. But I don’t know for certain. That’s why you’ll stay sane longer if you source these parts from just one car.
– Engine mount bosses. The 1969 and earlier engine blocks were cast with two drilled and tapped bosses or holes for the engine mounts, along the oil pan mounting flange. In 1970, because many of the new cars had undergone chassis redesigns, the new blocks were cast with 5 bosses to allow the engines to be mounted in either earlier (pre 1969) or later chassis.
Some of the blocks cast in the ’70s don’t have all of these holes either drilled or tapped. Others do. If your 455 doesn’t, it shouldn’t be too hard a job to drill and tap the required holes. Use a correct engine bracket for a guide.
The other recourse is to use engine change brackets available from Year One, Performance Years, and AMES.
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Content last modified: January 16, 2014 at 7:11 am
Q: V-8 Into a 6-Cylinder Compartment
I have a 400 block built and plan on putting it in the 1967 326. I was wondering what special bracketry I mich need to accomplish this.
A: If you use all of the bracketry from the 326 motor, you don’t need anything extra. About the only possible hang up is if your block is a 75 or older. After 1970, all Pontiac V8s were cast with 5 holes on each side to allow installation in either early or late chassis. Some 75 and later engines either don’t have all of the necesary holes tapped, or they aren’t present at all. New motor mounts are usually a good thing since after 33 years, the originals are a bit tired. In general, 326, 389, 400, 428, and 455 all interchange.
Other than that, this should be a simple bolt in. Just don’t try to interchange your 1967 accessories or brackets with any later stuff. You will risk pulley alignment problems.
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Content last modified: January 16, 2014 at 7:12 am
Q: Chevrolet Engine into a Firebird
I have recently bought a 1967 Firebird that rotted outside my bedroom window since I was 13. Now I am all grown up and own that car but there is no engine. It has the origional 400 transmission and I have a 1969 327 from a Vette but I am not sure it will bolt in as is. Can anyone advise?
A: It won’t be a direct bolt in as Chevrolet uses a different bellhousing bolt pattern that the rest of it’s corporate sisters (Buick Olds Pontiac). However, there are some relatively cheap adapters orderable from Summit, Jegs, PAW, etc, that will allow you to mate these two together.
In addition, you will need to get the motor mounts and frame brackets from a Camaro to seat the engine in the car. The matching holes should already exist in the subframe. You will also need Chevrolet accessory brackets for the power steering, alternator, smog pump, etc.
A: You’ll need to get an adaptor from Summit. It’s not in their catalog, you have to ask for it. It’s about $65. It will allow you to connect a Chevy engine to a Pontiac trans. Then, you will have to reroute the fuel line to the passenger side instead of the driver’s side. And lastly, you’ll need engine mounts to fit a Camaro (most parts stores). Most anything else you run into can be easily remidied. This will get most of it. If you can get a Pontiac engine, you’ll have a lot more low end torque though. Do what I’m doing, I put the chevy engine in just till I find and can afford what I really want, a 455!
A: Why not just sell the Corvette motor to a Corvette guy and buy a 400 or 455 for the bird. With the extra money you save on motor mounts,adapters,exhaust,carb linkage etc. you could even find a nice running Pontiac motor.
You dont say how mechanically inclined you are but I have a feeling that if you had to ask this question then you are already over your head as far as an engine swap. Besides your restoration will be worth more if its close to correct. If the car was a true 400 car(the only one that used a 400 trans) then I would suggest looking for a correct replacement.All of this also hinges on the condition of the car in its present state. If it is totally rotted you may want to consider another project.
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Content last modified: January 16, 2014 at 8:22 am
Q: Small Block Chevy in a 1968
I’ve just been offered a hard to refuse buy on a almost new custom built Chevy 350, 350 HP street engine (trust me – for the price you would consider it too). My ’68s 2 bbl is tired and needs a rebuild. The engine currently in the car is correct Pontiac but not numbers matching, nor is the transmission (I don’t have either of the originals). So I’m thinking about putting in the Chevy. I know some of you have done this, so what’s you’re experience? What do I have to do to make it work?
A: Given that the Firebird chassis shares so much with the Camaro, an SBC goes in quite easily. You need the following:
– Camaro engine frame mounts. Easily found at any source that sells Camaro stuff. Classic Industries, National Parts Depot, Year One, etc. Plus the rubber/steel engine mounts.
– Accessory mounts. You need Chevy brackets for the power steering, alternator, and A/C if so equipped (can’t remember if your car is so equipped).
– Accelerator stuff. This gets a bit tricky. The 1967-1969 Camaros used a rod linkage for the throttle, as did the 1967 Firebirds. The 1968 and 1969 Firebirds and other Pontiacs were ahead of the pace by using cable linkages. You need to change your linkage to the Camaro variety, which should utilize the existing holes in your firewall. You may need a Camaro or 1967 Firebird gas pedal assembly. I know where you’re likely to find one if needed. You also need whatever throttle/kickdown brackets are appropriate for the linkage and carb you will be using.
– Fuel line. The Firebird hard line comes up along the subframe from the the tank on the right (passenger) side of the car, then crosses over to the left side along the main front crossmember. The Camaro unit ends just past the crossmember on the right side. You will need to either cut your line, or replace it with the Camaro piece. Cutting the line will of course, make it more difficult to go back to a Pontiac engine.
That should do it.
Now, with some searching, I can imagine you should be able to find a recently rebuild or at least good running Pontiac 400, 428, or even 455 for fairly cheap. Probably not as cheap as the Chevy engine you found, but reasonable. Heck, you might even consider a reman. engine from one of the discount parts houses in the area. Pepboys, Kragens, etc.
Of course, you know I had to add this option. While I’m not a purist, I still dig Pontiacs with Pontiac engines. And your car is too cool to wear a bowtie. And I even own a bowtie car!
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Content last modified: January 16, 2014 at 8:23 am
Q: New Engine Break-in
I just got my Firebird back out after rebuilding it. It’s awesome when it idles you can hear the cam. If I’m cruizin at 30mph and I put my foot all the way on it – the tire spins. If I get on it from a stand still it spins all the way from first into 3rd. It dont let up till I do.
A: Thats not the way I would breakin a fresh motor. Have you changed your oil & filter yet?
Heres what i do:
– Run engine for 30 minutes high steady idle to breakin cam
– Drain oil and change filter, run 500 miles using new car breakin rules.
– Change oil and filter again.
– First few miles should be a light throttle then coast light throttle then coast.
This process will help in seating rings. NO full throttle blasts…. I know its tempting but its proven that the infancy of a fresh engine will pretty much determine its life. Have fun and make it last.
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Content last modified: January 16, 2014 at 8:24 am
Q: Engine Serial Number does NOT Match Vehicle Identification Number
I was told buy one of my local specialty wrecking yards that the engine serial number and the VIN number didn’t always match from the factory. I’m inclined to believe him. My 1968 convertible was built in Los Angles and it’s all original. Nowhere in my delivery documentation does the engine serial number appear, only the VIN and Body Tag data. My engine and VIN don’t match – not even close. What’s the truth here?
A: Short Answer:
* The VIN on the car should match the VIN on the Engine (68 & up)
* The Engine Unit (Serial) Number was a separate number stamped on the Engine. This number has nothing to do with the VIN and appears with the VIN on the Billing History.
So, you are correct when you say the Serial Number and VIN did not always match. Infact, they will NEVER match because they are different/separate numbers. If the VIN on the front of the Block matches the VIN on the Dash, that is the original correct engine for that car. You can also search for the B’Cast Sheet in the car, that will also ‘authenticate’ your car.
A: Engine ‘Serial’ Number (manifest number) has no connection whatsoever to the Vehicle Identification Number. This number was used within the Plant for sequencing. There is a VIN stamped on the block however that should match the VIN on the car. This is stamped on the front, lower face of the block next to the timing chain cover (way down low near the harmonic balancer). People have tried explaining the purpose of the Engine Serial Number yet, nothing official from PMD has ever surfaced explaining when it was stamped and for what exactly it was used for. My guess is that is was used by scheduling/sequencing in order to match a particular engine with a specific car. The VIN would have most likely been stamped on the engine just prior to going into the car.
While working on the 1967, 1968, and 1969 Firebird Registry, I have found that you can have two cars with very close VIN numbers and yet, their Engine Block Serial Numbers are hundreds (or even thousands) of numbers a part. The Engine Serial (Unit) Number can be found on the Broadcast Sheet and the Billing History Sheet. Once the car was built, only the VIN had any significance since the car, engine and trans (manual only) were tied together through it.
Here’s another clue about the Engine Unit Number…. Looking through Service Bulletins, if an engine issue is addressed, most everytime the Engine Unit Number is mentioned. Example: for the 1967 Firebird w/Ram Air, there were two types of Engines; the 1st Type was used up through Engine Unit Number 646615. The 2nd Type started at 646616. Another Bulletin addresses the issue of 1967 Cylinder Head Oil Return Passage Modifications. It lists those vehicles involved including the range of VIN numbers and the Engine Production Number involved. Based on these examples, I would say the Engine Serial (Unit, Production, Manifest) Number was stamped onto the block somewhere within the Engine Assembly Line (not the foundary) along with the Engine Usage or Application Code (Two-Letter). I say this because the Foundary did not assemble the engine and had no idea whether it was going into a GTO or Firebird and if it was to be a manual or automatic Engine. Once the Engine Assembly Line received the Block, scheduling would have given it a specific Usage Code (2-Letter) in order for the Line to install the correct components on the Engine. Perhaps the Engine Unit Number was stamped at this point as well (according to scheduling/sequencing). At some point following the Engine Assembly, the Engine Unit Number was ‘connected’ to a VIN in order for the Plant to know which engine to ‘pick’ (or schedule) for a specific car.
I doubt that 30yrs ago, the assembly plants were using the same sequencing (or “Just in Time”) delivery methods we use today however, I’m sure they did have some sort of scheduling/sequencing system. Also remember that the engine had a large white label with red letters attached over the two-letter code stamped on the front of the block. This was another aid in determining usage/application for a specific engine (much easier to read this white/red label than to squint to see the 2-letter stamped code). Anyhow, That’s my ‘long-winded’ opinion on the issue of Engine Unit Numbers.
A: I used to work at the GM assembly plant if Fremont, CA. Engines came fully assembled less optional accessories. I’m sure this was the case at the sister LA pant as well. When the engine s/n number was stamped I don’t know. But I do know that sometimes there were problems with engines after they were installed and were swapped out at the plant. Also, sometimes there were problems like more bodies than engines (remember Buick engines going into Chevys – it’s true!), and they would grab whatever engine they could find and throw it in to keep the line moving. For what it’s worth!
A: …Yes, Engine usually came to most Final Assembly Plants fully assembled. (Not always the case though). In addition to a Forging/Casting Plant, there was also an Engine Plant where they were assembled. I’d guess this is where the engine received its Serial Number stamp. This number was used by the Final Assembly Plant (for the vehicle) to coordinate scheduling/sequencing for the engine to body. No matter what the situation in the Plant, I seriously doubt that they would grab whatever engine they could to keep the line moving. Especially after ’67. Engines were sequenced with the body and were controlled for many reasons. The case of the Chevy/Buick engines was unique and different. Despite the mix of engines, all still had serial/VIN numbers stamped on them and they matched a specific car. It’s not like there was just this big batch of engines and a Line Operator going.. “eenie meenie minee moe….”
A: The VIN got stamped on the block starting in 1968. I have a 1968 Ram Air I, and the VIN on the block, just to the left (looking at the front of the engine) of the timing cover, matches the last 6 numbers of the VIN. This number can”t be seen unless you remove the lower radiator hose from the water pump housing, or if you get a mirror and shine a light down by the harmonic balancer, you can see it
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Content last modified: January 24, 2014 at 9:47 pm
Q: Valve Adjustment
I am about ready to put my engine back together but I can not find any information how much to tighten the valves.
A: The valve adjustment on a STOCK Pontiac is straight forward.Tighten the lock nuts to 20 foot pounds and your are done.Pontiac made it nice and easy.Even with the aftermarket cam I had in my 1967 400 I used this spec and had no problem for the 10 years I drove the car after a rebuild.
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Content last modified: January 16, 2014 at 8:25 am
Q: Decoding Engine, Carburetor, Manifolds
I know I had a reference to decode some of these numbers, but I have forgotten if it was a book or website. My engine has ‘YR’ and ‘33202’ stamped just to the left of the top of the water pump, and ’23N108627′ stamped below the water pump. The intake manifold has ‘E220’ cast into it and the exhaust manifold has ‘9796155’ cast into it. The numbers on the carb are 17054905 and just below, 2738. Would someone please tell me what these codes mean. Thanks.
A:
YR ….. This is the specific Engine Usage/Type Code
33202…. This is the Engine Unit Number
23N108627…. This is the partial VIN, unique to the car the engine came from
E220….. This is a Date Code (May 22 ’70 ?)
9796155… This is a Part/Casting Number
17054905…. This is the Usage Code for a Rochester Carb
2738….. This is the Build Date Code (273rd day of 1968 ?)
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Content last modified: January 24, 2014 at 9:46 pm
Q: Adjusting Valves on a 350
My son and I are having trouble adjusting the valves on our 350 small block. We just ported the heads (edelbrock) and tried to adjust them with a steatho scope… they have hydrolic lifters and new push rods… can’t get any power out of the engine and when we crank down on the valve the noise still is there…. any ideas on how to adjust them?
A: I can’t imagine of what use a stethoscope is while adjusting valves, but I’ll tell you how I do it. I usually performed this with the engine running, and the valve covers off – do this one at a time since it can get a little messy. You may want to lay a piece of cardboard or small piece of scrap sheet metal across the head to contain some of the oil. Set it inside the lower lip that the gasket sits on, and do one side at a time if you want to. Back off each rocker nut until that valve ticks, tighten until the ticking stops, then tighten some more. How much more? That depends on if the lifters are new or not. If new, turn one complete turn, if old, go a half turn, if not too old, go 3/4 turn. Reinstall valve covers and clean up oil splashes with CRC Brakleen.
Some people prefer the static (engine not running) method, it also works well, but takes more time.
A: Here is a simpler method. It still works for non poly-locks. This is from Rock and Roll engineering web site.
Poly lock nut adjustment for hydraulic cams
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Install poly-lock with hex end up. Thread in set screws a few turns with hollow hex end up.
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Make sure lifter in on the heel of the cam.
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In order to get a “feel” for the pressure of pushrod against lifter cup, push the pushrod into the lifter by hand so you can feel it’s spring tension. Tighten poly lock slowly while moving the pushrod up and down, being careful to stop turning the poly-lock just as the pushrod touches the lifter cup, and the up and down free play is taken up.
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Now turn the poly lock one more “flat”, or a sixth of a turn. Hold the poly lock in that location with a box end wrench. Turn the inside allen set screws down until it contacts the rocker stud. Snug it with the palm of your hand. Do not tighten!
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With the box end wrench in one hand and the allen wrench, turn both together until they tighten, or approximately 25 to 30 ft. Lbs. They must be tight, but you don’t want to be an ape either. Use common sense.
Warning! You cannot properly tighten poly locks by just turning the allen set screw.
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Content last modified: January 16, 2014 at 8:25 am
Q: Engine Codes
I am currently in the process of having my engine for my 1967 400 Convertible rebuilt. The mechanic has cross-referenced the (YD) code to a 1967 400, but it says it is a 2 barrell, and my engine has a 4 barrell. I am unable to find a cross reference for the engine code under the 1967 sectioin of this site. I do not see the letters referenced in this section. Can someone help me?
The code on the block is: 0081718 YD
Also stamped is: 20P105982
A: The 20P105982 is your clue to what that engine really came from. The first zero means it’s from a 1970 car, and the letter “P” means it was from a car built at the Pontiac assembly plant, where that year they were building full-sized cars like Catalina and Bonneville. The YD for that year indicates a 2 barrel 400, 290 gross HP from a Pontiac, meaning big car. Although the chart I have says a 10.0:1 compression ratio, it does not say what head cast numbers were used.
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Content last modified: January 24, 2014 at 9:41 pm
Q: Sluggish Motor
I am experiencing a problem with my motor running sluggish. While accelerating it runs fine but when you ease off to a cruising or constant speed, it seems as if it is missing and surging. I have replaced plugs, wires, points and condensor, and even taken the carb off and made sure there is no vaccum leak to the manifold. I am stuck! The only thing that I remotely have left is the distributor. Could this be the problem? Has anyone experienced anything like this? I appreciate any help.
A: Two things come to mind.First if there is excessive ignition advance it can cause the problem you describe.To find out,try disconnecting the vauum advance hose and plugging it then test drive the car.If it is now O.K. check the initial timing, amount of centrifugal advance and amount of vacuum advance.It is unusual but I have seen the internal limit “stop” in the vacuum advance can break allowing the rod to move way too far.You will need a vacuum pump and a “dial-back” timing light to do this check.The other thing is if it is running too lean a fuel mixture at cruise it will cause a surging condition (it would be better under acceleration due to the power system) This is a little trickier to test for.The easiest way would be with a gas analyzer which the average person doesn’t have access.A crude way of finding out is remove the air cleaner and plug and vacuum hoses removed then run the engine at 2000-2500 rpm (engine must be warmed up and choke fully off) Now partially resrict the air horn either with your hand or by partly closing the choke valve and see if the rpm increases.If the rpm picks up sharply and the motor sounds smoother you likely have too lean a mixture.The reason may be a number of things which I could only guess at with out more info.This test is admittedly a bit crude and requires a bit of experience to interpret the results of.
A: If your car has a Quadrajet, your throttle slide (the little brass cylinder that pulls your metering rods up and down) may be sticking. This happened on a 350 I had. Try pulling the top off of the carb and us a Scotchbrite pad to buff it up and see if that helps.
A: I found the problem with the motor surging on my bird. I pulled the distributor and found a wire to be dangling off of the vaccuum advance module. I dont know what purpose this wire served but one end had a screw which held it onto the module itself and the other end was bare just laying in the bottom of the distributor. I went to a local salvage yard and picked up an HEI distributor for 20 bucks and installed that in the car. (Much better than points system). Didn’t even have to beat the firewall in, went right in. I am soooo relieved. I was starting to think it was something mechanical. I thank everyone for the help you have given me.
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Content last modified: January 16, 2014 at 8:29 am
Q: 400 Engine Block Code for 1967
I’m trying to decipher a code cast into the block on my 1967 firebird. The code is located near to where the distributor fits into the block. I think it is the cast date of the block but I would like to know for sure. The code is 86133. (As best as I can tell).
I know this isn’t the sequential build number, (serial number), of the block since that is locate on the front on the block on the passenger side of the car.
I’d appreciate any information you can provide.
A: That is the blank block casting number. It’s like a part number. According to my info the whole number is 9786133. This denotes a 1967 400 cid block. I got the info from a book called Pontiac Muscle car performance 1955-1979 by Pete McCarthy
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Content last modified: January 24, 2014 at 9:41 pm
Q: Oil Dipstick Tubes For the 1968 400
What is the correct tube for a 400?
A: After some research into the question of oil dip stick tubes for the 400 firebird I found that it has three tubes.
The first is in the oil pan, the block to baffle tube, a short curved piece about five inches long and copper in color. The second is about nine inches long and ever so slightly curved, which extends from the outside of the block to the third and final section. Lastly, the third tube runs up from the end second tube to where it itself ends, just above the rocker cover. The dip stick itself is inserted and held into the third tube, which has a small bracket that attaches to the front outside rocker cover bolt. The GM numbers for these are as follows: block to baffle #546281 9″ curved (GM calls it straight) #9795830 upper #480843
I was able to purchase all but the upper of these at my local pontiac dealer. That one they stocked, but were temporarily out of.
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Content last modified: January 16, 2014 at 8:30 am
Q: Engine Unit Number Does Not Match
The engine unit number stamped on my 1968 does not match the Billing History but I know it is an original engine. The engine code is WK, and the number next to that is 205848, engine unit production number per the Firebird page Tech info and has no reference to VIN number. Then the “engine unit number isted on the PHS Billing history is 205818. Note the number varies in one number: 4 vs 1. Could this be a miss stamp or some type of mistake.
A: Engine Unit Number is the number stamped on the fron of the Block next to the Engine Code. Also found on the Billing History. These numbers should be the same. The Engine Unit Number and partial VIN were stamped on manually and were not as deep as the Code stamp. Also, there was not alot of quality assurance & certification back in 1968.
The Gang-Stamp Tool could have slipped during the strike causing a partial stamp. Wouldn’t doubt that a mis-stamp could have happened either. Considering the numbers you shared are so close, seems obvious they are one in the same… despite their seemingly different appearance. I wouldn’t lose any sleep over it. Who would believe that you had the wrong engine and it just happened to be 30 units different from the original ?
A: My guess is that the digit “4 ” is correct and that the digit”1″ stamped into your block is a weak stamping of the number “4”.Ive seen several weak stampings of production #s and VIN #s Some of which appeared to even skip a digit. This was actually a very weak stamping and had only a small portion of the number visable. Take a real close look, Im betting its a 4.
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Content last modified: January 24, 2014 at 9:42 pm
Q: Dipstick Problem after Rebuild for 1967
I just rebuilt a 326 Pontiac motor to put onto a 1967 firebird. Before I had it rebuilt the dipstick was fine like it should be. But when I got the finally put in the car and fired it up the dipstick shoot right out of the the motor. I got out of the car with it still running and started to put it back in the motor but it keeps hitting on the cam. CLICK CLICK CLICK I even order a new tube and dipstick together and put it in. I still have the same problem. I was wondering if you knew what could be the mess up? Thanks
A: I posted a similar problem on one of the performance years pontiac boards. When you replaced the tube, do you mean the external tube, accessable from the outside of the engine? Sounds to me like your inner tube is bad. You have to pull the oil pan to replace it. To do this you may have to pull the engine or if you’re lucky you can just remove the distributor and jack up the engine to get it off. The lower tube inserts into the block from below. That’s as much as I know since I haven’t actually done this yet, I still have the click click problem unless I put in the dipstick just right.
A: Your dipstick is hitting the crankshaft and sorry to say I think that the lower portion is bent or missing. You may have to PULL the oil pan to see what is going on down there. You didnt mention if the car has A/C or not. A/C cars use a different dipstick and dipstick tube perhaps you have a short tube and a long dipstick. You can check this by putting the car on level ground and check the oil level on the dip stick. With 5 qts. in the pan you should read about 1/2 qt low on stick.
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Content last modified: January 16, 2014 at 8:31 am
Q: Engine Code Confusion for 1969
I’m completely confused about the the engine serial # vs. the partial vin # on the engine….
A: In 1969, the partial VIN was stamped on the front, RH face of the Engine. It could also be found on Manual Transmissions in addition to the “hidden” partial VINs stamped onto the Body Shell. Besides the VIN plate attached to the upper RH Cowl (dash), there was also a Fisher Body Trim Tag attached to the RH Cowl (firewall).
Documentation for the 1969 Firebird (sequentially listed) consisted of:
1) Chassis Broadcast Copy (for engine/chassis Line Workers)
2) Body Broadcast Copy (for Trim & Final Line Workers)
3) Car Billing Invoice (for accounting)
4) Window Sticker (for dealer/customer)
5) Owner Protection Warranty Protecto-Plate
The VIN was used to identify the Vehicle Division, Assembly Plant, Body Style, Vehicle Series, Production Model Year, Engine Type (6cyl, V-8) and Sequential Unit Number. (NOTE: Vehicles were not always built completely sequentially per VIN) ((More on that later)). The VIN is found on all Documentation.
The Fisher Body Unit Number was used during the Scheduling Phase for both Fisher Body and the Final Assembly Plant. For 1969, this included Lordstown, Norwood and Van Nuys. Each plant used a different method for assigning this number. Despite what many people claim, this number was NOT entirely a Sequential Unit Number. Vehicles were built in batches; The VIN was assigned from a batch set of numbers. Build Scheduling was based on many factors and not simply on who ordered first. As with the VIN issue, the Body Unit Number requires a more in-depth explanation. ((coming soon to a web-site near you)). The Body Unit Number can be found on the Broadcast Copies, Protecto-Plate and the Window Sticker.
Starting in 1969, the Fisher Body Unit Number and Identification Number (as noted on the Broadcast Copy) were both the same numbers. On the Car Billing Invoice, there was another type of Identification Number used for accounting purposes only.
The Invoice also noted the “Dealer Order Number” (for accounting).
The Broadcast Copies also used a “Sequence Number” (3-digits). This was used for scheduling batch builds at Fisher Body. No sequential connection to any other numbers.
The Trim Tag Date Code refered to the Fisher Body Scheduled Build Date (week & month). This was for the “Body in White” (bare shell) and not the Final, fully assembled vehicle. The closest date for Final Assembly can be found on the Invoice. There were (3) different dates identified: – “Date Shipped”, “Date of Note”, “Date of Execution” The “Date Shipped” would usually be no later than a few days of when the vehicle actually left the Final Line Certification Buy-Off.
The Engine Unit Number for the 1969 Firebird (stamped on the RH front face of the Block) was used during Engine Assembly (Sub & Final) and for the Engine Installation Sequence at the Final Assembly Plant. The Engine Unit Number can be found on the Protecto-Plate and the Chassis Broadcast Copy (not Body Broadcast). Starting in 1969, the Engine Unit Number was not used on the Car Invoice. Once the Vehicle left Final Assembly, the only purpose for the Engine Unit Number was for Warranty related work which is why it was stamped onto the Protecto-Plate. The Accounting Dept. used the VIN and their own “Identification Number” found only on the Car Billing Invoice (microfiche files from PMD). This Number was used for billing between the Assembly Plant, Accounting and the Destination Dealer.
In order to verify a correct numbers matching 1969 Firebird, the VIN on the Dash must match the VIN on the front of the Engine Block. Unless you have the original Protecto-Plate, the Engine Unit Number cannot be verified since it was not related to any other vehicle number.
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Content last modified: January 24, 2014 at 9:42 pm
Q: Oil Spraying Out of Dipstick
I just recently purchased a 1967 bird with a 400 and an automatic tranny. It needs some work but for the most part is all original. The motor has 670 heads and is a YT.
The engine seems to have a lot of power but when I rev it very high I get oil thrown out of the dipstick tube onto my exhaust manifolds. I suspect the bottom end of the tube is missing or the windage? tray is not installed. I am the third owner of the car. The second owner told me that the engine had been rebuilt. Bored .40 and bigger cam installed, heads have been redone.
A: Oil spray out of the dipstick tube could mean excessive blow-by (i.e., the rings are gone or broken ring). Run a compression check before you break the motor down.
A: I had the same problem when I installed after market valve covers. I was waiting delivery on a oil breather, and since I had just installed headers and a RPM performer manifold I didnt want to wait for it, so I just blocked the cover off and took it out for a run. Guess what, oil shot out the dipstick due to back pressure. Suggestion to original question. Make sure there is a clean unblocked breather on one of the valve covers.
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Content last modified: January 16, 2014 at 8:32 am
Q: Engine Date Code for 1967
I have confirmed that the engine number on my 1967 is: 415371 is the motor unit number, YT is the engine code: 400 AT with AIR, and the number on the distributor pad, is actually 9786133 and denotes a 1967 400 cid block.
What I am curious about is if there is any sort of build date number located anywhere on the block or encoded in the motor unit number itself. The reason I am interested is that I would like to find another 1967 YT motor for my car. The build date on my car is 03 B, which translates into the second week of March. Since GM didn’t start stamping the engine blocks with the car’s VIN until 1968, all I need to do is locate a 1967 YT block which has a build date of prior to the second week in March, providing the blocks have/had any build dates associated with them in the first place.
So, if I am going to go through the hassle and expense of finding another YT block, I need make sure that the block I do find would actually be date correct for my car.
A: I got the following email reply to a simliliar post I did to rec.autos.antique. It explains where the date code is, and how to decode it. I checked on my motor and sure enough, my date code is B157, which is a build date of 2/15/67. Which makes perfect sense if the build date of the car was the second week of March. So, I thought I would share the information with the list:
You probably saw the build date code and just didn’t recognize it. On the top surface around the distributor hole you will find a code that starts with a letter and has 3 digits. The letter indicates the month, the next two digits are the day, the last digit is the last digit of the year. In your case a correct date code might be B077. This would read “B” = February, “07” = 7th day of the month, “7” = 1967.
The only time this gets fuzzy is with the use of the letter “i”. Some factories skipped the letter so that it would not be confused with a “1”. However this is not a perfect rule, some factories did use it but not all. The other problem you will have is that since your vehicle was built early in 1967 there are a lot fewer motors to choose from as Pontiac just moved from the 389 to the 400 in ’67. To be totally authentic you need a date code within about three months of your build date. Engines weren’t left laying around any longer than that and a judge in the really picky levels of competition will count off for anything outside of that.
A: Check out the date code near the distributor. It’s 4 digits, starts with a letter and 3 numbers. The letter is the month A=Jan, B=Feb…the last digit is the year. Starting in sometime in Sept the engine would be for the next model year. If you have any questions, post the code.
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Content last modified: January 24, 2014 at 9:43 pm
Q: Original Oil Filter
Wanted to know if anyone knew anything about PF23 AC oil filters. I ran across a NOS one that is white with blue stripes and red AC logo on it. On the box the only application listed is 1967 Pontiac V-8. I am sure it was superceded by the PF24. The 1967 Firebird parts manual supplement that is dated effective February 1967 lists only the PF24, the 72 Pontiac master parts catalog lists all PF24, no PF23 for anything. What would be correct for a 1967 bird built third week in May if it just rolled off the assembly line????
A: Just curious as to why you want an original oil filter, be it a PF-23 or PF-24. To be 100% correct as it was at the showroom fresh off the assembly line it would be painted PMD metallic blue. The AC identity would be obscured. There are lots of reproduction AC filters out there. Go to K Mart buy the latest AC filter and paint it PMD metallic blue. I wouldnt run an 30 year old design filter on a $20K restored car anyway. No more than using 30 year old oil. Just trying to save an engine an some money.
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Content last modified: January 16, 2014 at 8:33 am
Q: Ram Air Features for 1968
*Please review and advise on any discrepancies. If you have corrections, please provide references for verification (Pt.No’s., etc.) Thanks !
1968 Firebird Ram Air Features…
ENGINE BLOCK
Casting Number… 9792506
Codes… WI (RAI-MT), XN (RAI-AT), WU (RAII-MT), XT (RAII-AT) {4-Bolt Main}
CYLINDER HEADS
Casting Number… 31 (RAI ‘D’ Port) 96 (RAII Round Port)…’stamped’
* Not all “96” Cyl.Heads were stamped
EXHAUST MANIFOLDS
Ram Air I & H.O….. Cast Iron Long Branch (‘D’ Port) 9779424-R…9779495-L
Ram Air II….. Cast Iron Long Branch (round-port) 9794036-R…9794038-L
* w/Thermostatic Heat Control Valve in RH manifold
AXLE
3.90… “ZP” (4-Pinion)
*No Ram Air Firebirds came from the factory w/4.33axle although it was available. Safe-T-Track was mandatory.
TRANS
Manual Trans… M-21 Close-Ratio Muncie (“FX”)
Auto-Trans… T.H.M (“PQ”)
* ALL 1967-1968 Ram Air Firebirds came with two-piece speedo cables and gear reducers. ((( ? PART NUMBER ?)))
INTAKE MANIFOLD
Casting # 9790140 (1st Type…. all 4Bbl’s incl. the RA I… exc. RA II)
Casting # 9794234 (2nd Type….all 4Bbl’s incl. the RA II … after May’68)
CARBURETOR
RAI…. (MT) 7028277 (AT) 7028276
RAII… (MT) 7028273 (AT) 7028270
CARB. VAC. BREAK CONTROL
Pt. # 7038237 (Ram Air I) …Black plastic Cover
Pt. # 7038239 (Ram Air II) …Green Plastic Cover
THROTTLE CABLE BRACKET
Pt. # 9792242 was used on the 1st Type Intake Manifold (9790140)
Pt. # 9797415 was used on the 2nd Type Intake Manifold (9794234)
* 2nd Type stamped “F-4”
OIL FILTER ADAPTOR
(Alum.- filter to block) *Used on all RA & H.O. engines Pt.# 9794111
DISTRIBUTOR
Pt. # 1111449 (exc. RA II)
The Ram Air I cars used the same Distributor as found on 400 M.T. and H.O. cars
*Only the RAII had a unique Distributor, Pt. # 1111941. (MT or AT)
RADIATOR
All Ram Air cars used the H.D. Harrison Radiator.
Manual Trans: “UQ”
Auto Trans: “UP”
RAM AIR HOOD BAFFLE
(pentagon shaped stamped sheet-metal pan, screwed to hood)
Pt. # 9793161
RAM AIR HOOD BAFFLE SEAL
Pt. # 9789883
RAM AIR CARB. SHROUD (Air Inlet)
(round stamped sheet-metal ‘tub’, set on carb.)
Pt. # 9792987
RAM AIR CARB. SHROUD SEAL
Pt. # 9793163
RAM AIR AIR FILTER ELEMENT COVER (black)
Pt. # 6424398
RAM AIR AIR FILTER ELEMENT
Pt. # 6421746 (A212CW & A-274C- paper wetted)
RAM AIR HOOD SCOOPS
(Cast-Metal Scoops “open”)
Pt. #9794283/84
NOTES:
* All Ram Air cars were shipped to the dealer with the Ram Air Baffle, Shroud, Air-Filter, Seals and Open Hood Scoops shipped in the trunk. From ’67 until early 1968, the parts were removed from the trunks and returned to the parts-crib by guards/inspectors while preparing to ship as they suspected theft. This discrepancy was corrected and it is assumed that parts were forwarded to the dealership for installation.
* All Ram Air cars came with a standard 4-Blade Rad’t. Cooling Fan unless optioned with the ‘Flex-Fan’.
* Ram Air Firebird’s ordered with the Ram Air Option and Underhood Lamp were modified at the Dealership in order for the Lamp Assy to clear the Hood Baffle. The Lamp was moved slightly outboard to clear the Baffle.
* The Underhood Structure req’d. a modification to the RH side near the Scoop in order to allow proper fit/sealing of the Ram Air Baffle & Seal. This was performed at the dealership while the Ram Air parts were being installed. A small section of the Underhood Metal was snipped away. In most all case’s, this was a crude alteration and is usually quite noticeable.
* The Code used on the Broadcast Sheet for Ram Air Engines was “Y”.
* No identifying codes were noted on the Firewall Trim Tag and/or VIN to indicate the Ram Air option.
* Less than 50 Ram Air Firebird’s have been accounted for to date.
* The Ram Air I production was from Aug 1967 until May 1968.
* Ram Air II production started May 20th 1968. The option code was still “347” however, the package price was increased. (sometimes found noted on the Billing History).
* Earliest known RA I was built in Oct. 1967 (Verdoro Green)
* The last 1968 RA II ‘Bird produced was invoiced Aug. 6 1968 (4spd coupe)
*For more information…please contact John Schuh FRamair@aol.com
“GENERATION-1 Firebird Registry” http://members.aol.com/Framair/Gen1.html
A: If you were surprised about the “standard” block for the 1967 Ram Air cars, how about learning that most of the blocks for the 1968 Ram Air II engines were “standard” 400 cid blocks (9790071) that were fitted with four-bolt caps!!! Some had the last four digits ground off and were re-stamped with —“2506”, but most were left with the 9790071.
Also your 1967 and 1968 lists show that the cylinder heads had their numbers stamped on them. Not so! All of the ’67 Ram Air “997” heads and the 1968 Ram Air I and II (“31” and “96”) heads were cast!!! Any heads with the numbers stamped on them were done by racers to satisfy the folks at the NHRA, for drag racing.
Find that information on a build sheet or trim tag!!!
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Content last modified: January 24, 2014 at 9:32 pm
Q: Oil Filter Replacement
The part catalogs do not go back far enough anymore and I did not write down the number I needed. Does anyone know what is the correct replacement for our oil filters?
A: Use A/C filters PF-24.
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Content last modified: January 16, 2014 at 8:35 am
Q: 350 HO Codes for 1968
What were the possible options and codes on my:
1968 Firebird 350 H.O.
L-76 H.O. Engine, 4Bbl Carb, Dual Exhaust, “H.O.” Side Stripes
A:
Engine:
350 H.O. Man. Trans. “WK” 320 H.P. 10.5:1 Compr.
350 H.O. Auto. Trans. “YM” 320 H.P. 10.5:1 Compr.
Trans:
3-Spd. Standard (C/S) Saginaw “RJ”
3-Spd. Standard (F/S) Dearborn “DB”
4-Spd Optional Muncie “FX”
2-Spd Auto ST-300 “MB”
2-Spd Auto (w/A/C) ST-300 “MC”
Cylinder Heads: “18”
Carburetor: M.T. 7028269 A.T. 7028266
Intake manifold: (same as all 4Bbl) 9790140
Exhaust Manifolds: (same as Std. & 400) 9794320RH/9777755LH)
Distributor: M.T. 1111447 A.T. 1111282
*There were 2,087 400 H.O. Firebirds made in 1968. I’d guess that there were close to that for the 350, perhaps less.
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Content last modified: January 24, 2014 at 9:44 pm
Q: A/C Reserve Vacuum Tank
I have a small coffee can shaped vacuum canister that I found underneath the drivers side fender mounted to the firewall on my 1968 400 convertable. Any ideas what it is used for? Appears to have never been hooked up. The manual doesnt help.
A: It’s the A/C reserve vacuum tank.
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Content last modified: January 16, 2014 at 8:35 am
Q: Carburetor Codes
I’ve posted this carb number a couple of times and the only response I received was the number didn’t match anything. So I’ve triple check the carb number and this is really it. So the question is can anyone identify the carb.
7037262
A: Its a 67( 4th digit) and is for a late half of year(3rd digit) with Calif emissions V-8 automatic( last number is even, odd is a stick shift.) Doesnt show as a Firebird tho. Still a rare carb for some GTO guy, to trade for a Firebird carb maybe. I wouldnt spend alot of money fixing the incorrect carb.
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Content last modified: January 24, 2014 at 9:31 pm
Q: Firewall Difference Between AC and Non AC for 1968
I’ve been working on my 1968 Firebird. The car originally had AC, but most of the components were not reinstalled when someone swapped the 6cyl for a V8. I’m not concerned with the car being original so I’m not going to try to put AC back on it. The heater blower motor case for my car also housed the evaporator core (I think that is what it is called). I was hoping to use the much smaller heater blower motor case off of a non-AC car, but according to the Ames catalog it “won’t work on any car which was originally equipped with AC”. Can someone tell me what is different about the firewall between cars with and w/o AC…. or can I make the non-AC case fit on my car?
A: The holes in the firewall are different for A/C cars. The hole for the A/C is about 6″ wide and 11″ tall. The heater only firewall is about 14″ long and 5″ tall (all dimensions are very approximate). Narrow tall vs short long… so to speak.
I had a 1969 400 that someone removed the A/C box and replaced it with a standard heater. He simply took a piece of sheet metal and covered the original hole (using silicone and pop rivets and cut a new hole the shape he needed. The heater cover will bolt right up after drilling a couple of new mounting holes. He painted the firewall all the same color and overall, it didn’t look too bad.
If you decide you want to do this and need the heater box and controls (different on non-A/C cars) let me know. I got a couple I’ll let go CHEAP.
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Content last modified: January 16, 2014 at 8:37 am
Q: Timing Chain Cover Replacement
I found the timing chain cover to be crack and a waterpump with bad bearings. My car is a early 1968 with a cast iron waterpump. I understand the timing chain covers and waterpump on 1969 and later are different. Does anyone know if these are interchangable?
A: 1968 and earlier engines used an 8 bolt water pump and matching timing cover. The 1969 and later use 2 flavors of an 11 bolt pump, and basically 1 flavor of 11 bolt timing cover, part number 482893 or 9796345.
So, to answer your question, you can convert to the later 11 bolt timing cover as long as you use an 11 bolt water pump, and the matching pulleys. You have to be careful to get the pulleys that match the water pump. There were 2 variants offered in 1969. Basically, get a 1970 or later pump, and get the pulleys and brackets for a 1970 and later V8 and you’ll be OK. All Pontiac V8 timing covers will fit all Pontiac V8 engines.
Otherwise, look for a 1968 timing cover, part number 9790346. The 1967 V8 has a different part number, 978129, but I don’t know how it differs. 1966 and earlier also have a different number. I believe they differ in the location or appearance of the timing marker. This could also be true with the unique 1967 and 1968 covers as well.
Some used parts vendors such as Frank’s Pontiac Parts in Ramona, CA, Steve Hanson in northern CA, or even Firebird (Camaro) Specialties have clean used covers for sale. It may be easier to locate a 1968 cover than find a later cover, and get the right pulleys and brackets so that all of your belts line up correctly.
A: The timing chain cover averages 125.00 or more and mine was pitted also from age and you cant file them down because the pullys will no longer match up so I shopped around and found Jim Butler Pontiac has the best price. That was hard to beat. His web site it http://www.jbp-pontiac.com
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Content last modified: January 16, 2014 at 8:38 am
Q: Low Oil Light on New Engine
Just started the new motor in my 1968 bird. I am running a grind cam, hydraulic lifters, and a summit cheapy oil gauge. I have two problems. 1 there are 2 collapsed lifters that never pump up, and low oil pressure at idle (if the gauge is good).
1. Would a bad lifter cause low oil pressure? or vice versa? 2. What else could I have done wrong on the assembly? are there any oil plugs that I don’t know about?
A: I don’t know if this is your problem but it is one thing to look for from my experience. I put a new cam in my 350. After this I had verrrrry low oil pressure (5 PSI at idle) for about 300 miles. I talked a guy at my local speed shop and he said that I probably scratched a cam bearing when I installed it (which I probably did because I did not use an installation tool like one should). He also said that after break in the oil pressure should come back. He was right. The car is now running good oil pressure.
I’m by far not an expert but I don’t think a collapsed lifter would cause low oil pressure but I’d think that low oil pressure could cause a collapsed lifter.
I can’t think of any oil plugs or anything else that could cause low pressure. My guess is that you have a scratched cam bearing.
A: Your lifters may not be bad. They may not have been properly primed before you installed them. Before you disassemble your motor try this:
1) Completely loosen your non-oiling rockers
2) Use the push rods like a straw and with a pump style oil can, fill the push rod with oil.
3) Oil the rocker and reassemble then adjust your lash (do not torque them down at this point).
4) Start your motor and allow it to run.
5) If the lifters are OK it should start to pump oil (if the rockers clatter, adjust until quiet).
6) As the motor warms the rocker will start to clatter, adjust until the clatter stops.
7) repeat step (6) until the stud nut bottoms out.
8) Re-torque to 20 ft-lbs.
This worked for me when I had a couple of non-oiling lifters on a stored motor. Good luck.
A: I had the same problem and discovered that the oil gallery plugs had been removed when the block was cleaned. There are two behind the timing chain cover at the end of the lifter galleries and one in the at the back of the block. The rear plug is a screw in type located behind an expansion plug. The condition described exactly matches the problem I had once I had discovered/installed the front plugs, but not the rear. The engine would run, but the last two lifters just would not pump up.
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Content last modified: January 16, 2014 at 8:39 am
Q: Oil Pressure is Low
I just rebuilt my engine and installed a new mechanical oil pressure gauge. It shows I am running with very low oil pressure. Can I still drive it to break it in and hopefully solve the oil pressure problem on its own?
A: First off… this is your motor and your money so you need to do what’s best. Running a motor with low or no oil pressure is VERY damaging. This is only a suggestion for something to check. ..
You mentioned it’s a new mechanical gauge. Is there a lot of air in the line? If so, lower pressures may not register until you sufficently compess the air… i.e., “Pressure about 60 lbs at 3500 rpm estimated”. Try bleeding the line to remove the air.
Once you have established you have oil pressure at idle the next suggestion applies… It’s not uncommon for new motors to have problems getting oil to the rockers. If the lifters were not primed properly they will not pump. Here is something that worked for me. Loosen the rockers and slid them to the side. Use a pump can with oil and fill the pushrod. Slid the rocker back and tighten until you cannot twist it between your fingers. Do not torque them.
Once all the pre-oiling is completed, start the motor and see it they start pumping. Thighten until they stop clattering — one at a time in 1/4 turn increments. If they are still pumping, keep tightening. Once you bottom out, you can torque the nut. Be aware that this is VERY messy. I used cardboard to fill the gap between the head and fender and fender covers to keep it off my car as much as possible.
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Content last modified: January 16, 2014 at 8:40 am
Q: Electrical Kickdown Switch on a 1967 400
This car is original, but the engine/trans have been out before, so who knows what small parts are missing.
The passing gear on the transmission has never worked. When cruising about 35 mph, if you floor it, it just slowly(relatively) accelerates. It seems pretty obvious that it is not downshifting. The trans is rebuilt and has no problems shifting normally otherwise.
I found an electrical switch on the back of the trans that I was told was the kick down switch. I followed the wiring harness bulkhead on the the firewall, and have absolutely no idea where it went from there. Does the gas pedal actuate a switch that tells the trans to downshift?
Any thoughts/answers would be greatly appreciated.
A: Yes, the Turbo 400 has an electrical kickdown switch. I’m not sure where it is supposed to be located on a 1967 bird, but it will either be at the carb throttle (rare) or under the gas pedal. It should be set up so the switch activates at around 3/4 throttle or so.
Here is text from a reply by Jim Hand on the classicalpontiac web page (www.classicalpontiac.com) which explains kickdown/modulator funciton on TH400.
Folks, Here is some additional information on the Detent circuits (kickdown switch), and modulator function on a T 400.
The vacuum modulator is the prime controller of shift points when vacuum is available for a signal. However, as there is not adequate vacuum available at full throttle, regardless of what gear is being used, the modulator has no control over full throttle shifts.
Here is a summary of operation: The detent system (kickdown system or passing gear) on a T-400 has several functions. In addition to activating the kickdown gear (may be 3 to 2, 3 to 1 or 2 to 1), it also overrides the vacuum modulator circuit. Since most engines at wide open throttle (WOT) under load have little or no vacuum, the modulator has no reference point, and adjusting it will make no difference in shift quality or shift rpm under WOT load. The detent system replaces the modulator as controller of shift points at WOT, and it must be operating correctly before attempting to adjust the governor for higher rpm automatic shifts. The detent system also modifies accumulator pressure to increase oil pressure to the clutches for increased durability, so it is vital that it be functional in all cases.
All this means that if the kickdown switch is incorrectly adjusted to function at part throttle, the transmission will act as if the throttle is wide open in respect to the next gear change whenever the switch is activated. As quickly as the detent switch is off (by letting off on the throttle), the shift pattern will return to control of the modulator, because there will then be adequate vacuum for the modulator to function. It also means that if a T-400 is run without a correctly operating detent system, the clutches will suffer accelerated wear because the oil pressure is less at full throttle shifts. Additionally, the WOT shift rpm points will be lower without a correctly operating detent, or kickdown system. The detent switch should be adjusted towards the full throttle end of the accelerator pedal range.
A: Yes, the 1967 Firebirds with the Turbo 400 transmissions use a switch activated passing gear, (kickdown). The switch is a plunger style unit which is mounted to the intake manifold near the left rear of the carb. The bracket is secured to the manifold via the left rear carb bolt which holds the carb on the intake manifold. The switch is then secured to the bracket via it’s threaded neck, through a large hole in the bracket. The switch gets activated by an extension bracket which attaches the pedal linkage to the carb. There are two wires connected to the switch, one is black, the other is black with a green stripe.
The GM part number for the switch is #9785545 (same…. 65-66 P/8 M-40, 1967, 1968, and 1969 F/8 M-40).
I believe Classic Industries sells a reproduction of the extension bracket which mounts to the carb.
I haven’t seen anyone with a reproduction of the bracket which mounts the switch to the intake manifold. However, I went through many a junk yard looking for this switch before finding a guy who located an NOS switch for me. I “may” have a manifold bracket laying in my junk parts bin, I’ll check when I get home. If I have one, it is yours.
Let me know if you need pictures of this setup. You WON’T find them in ANY Pontiac, Firebird, or GM service manual, and there is no reference in any Firebird wiring diagrams that I have run across. I’ll be happy to take a few pictures and digitize them for you.
A: See also Engine F.A.Q. – Carburetor for more Kickdown Switch Information.
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Content last modified: January 20, 2014 at 10:26 pm
Q: Oil Recommendation
What oil is recommended for my 1968 engine.
A: My 1968 owner’s manual says that non detergent oils are specifically not recommended. It recommends the following SAE Viscosity Numbers:
Above Freezing (32deg.F.)………………… 20W or 10W-30
Below Freezing (32deg.F. and above 0deg.F.) …10W or 10W-30
Below 0deg.F……………………………..5W or 5W-20
All high output (H.O.) engines require the use of SAE #30 oil in the summer (above 32deg.F.) and SAE 5W-20 oil in the winter (below32deg. F.)
SAE 5W and 5W-20 oils are not recommended for sustained high speed driving.
SAE 30 and SAE 20W-40 oils may be used at temperatures above 90deg.F.
SAE 5W-30 oils may be used at temperatures below 32deg.F.
SAE 10W-40 oils may be used at temperatures between 0 and 90deg.F
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Content last modified: January 16, 2014 at 8:42 am
Q: PCV Purpose
Is the PCV valve required for crankcase ventilation if I have a breather in my valve cover?
A: The purpose of the PCV is to ventilate the crankcase of by-pass gases and while helping to prevent any positive pressure buildup which will blow oil past seals and out your dip-stick tube. These gases contribute to oil breakdown and internal varnishing. Using your intake vacuum as a source, the gases are “pulled” from the crankcase. Just having a vented breather is not enough to properly ventilate the crankcase.
Q: Ok so I have to have the PCV valve (I was hoping you would say I didn’t!) Does it have to be located in the valley pan or can it be in the valve cover? I bought a replacement valley pan made out of rolled aluminum and it doesn’t have a hole for the pcv valve. Also. isnt the PCV valve a piece of smog equipment? What did early cars say from the 50’s have for crankcase ventilation?
A: Installing one in the valve cover will work fine. Before PCV valves, most motors had an open vent tube coming from the lifter galley. Typical on early SBC was a vent pipe the attached behind the distributor to the block. The other end had a “baffle” at the back of the lifter galley. On a weak motor, you could see the blue smoke coming out of the vent tube under the car. Imagine the smell! And by the way… another reason the have a PCV valve is to help reduce engine blow-by odors and fumes inside the car.
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Content last modified: January 16, 2014 at 8:43 am
Q: Voltage Regulator Mounting on a 1967
Could somebody please look at their 1967 and tell me how the voltage regulator mounts? I took mine off of project bird over a year ago and am having troubles figuring exactly how it goes back on. The regulator has 3 mounting holes but I can’t seem to get 3 holes on the rad. support that match up. There seem to be lots of holes in the vicinity and one hole has a rubber grommit in it.
A: The regulator mounts to the hole with the rubber grommet, plus two others that used to have grommets, way up near the top of the support. One of them is actually under the lip when viewed from the front of the car. Holes are about 1/2″ diameter. BTW the rubber grommets have a built in threaded insert that the regulator screws go into, and compress them, sort of like a pop rivet does when you install one.
A: thanks for your response on the voltage regulator mounting. I found the three holes and even found new rubber bushings with nuts (called well nuts I found out) at Kragens Auto Parts.
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Content last modified: January 16, 2014 at 8:46 am
Q: Accessing the #2 Plug
I need to know if I do, in fact, have to move the a/c compressor to get to the #2 plug.
A: I move the compressor to get to the plug. I don’t know about the other guys, but I prefer using up the time to save me frustration!
A: #2 plug is easily accessed by going thru the inner fender seal (mud flap). You may want to jack up the front end and remove the tire for real easy access.
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Content last modified: January 16, 2014 at 8:47 am
Q: Spark Plugs on 1968 – #8 Plug Inaccessible
I have a 1968 400 with A/C and have never been able to contort my arm just right to get the number 8 plug out because of the close quarters to the A/C. I’ve had to take it to a shop to put it on a lift to get at it from below and even then, the mechanics bitch about it. A couple have said they didn’t think it should be that tough and my engine mounts may be off kilter, but they don’t know enough about Firebirds to know for sure. Anyone else have this problem? Anyone have the measurements I need to verify if my engine is sitting in the right place in the bay? Anyone have any tricks to getting at that #8 plug, I’ve tried everything (from top, from below, through the wheel well) and always end up cursing the thing out.
A: I have had the same problem on my 1968/350 with air. I have been able to get it out using a spark plug socket and turning the socket with an open end wrench. I have to do it by laying under the car. My arms usually go numb three of four times during this operation from the cramped quarters and working over my head. It is a major pain to get out.
A: The best plan of attack is to remove the rf wheel and go in through the wheel well.Snap On tools makes a 3/8 drive ratchet in a 1/4 body that works great for stuff like this.I have worn mine out 3 different times from using it so much on the new cars of today. Break the plug loose with a wrench on a short plug socket (they are all not the same) and then use the ratchet to take it out until you can turn the plug with your fingers.
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Content last modified: January 16, 2014 at 8:48 am
Q: Cam for a 1968 400
I’m trying to track down the stock spec’s for the cam in my 1968 Firebird 400 conv. It has no performance upgrades that I am aware of, any help? Lift, duration, lobe sep, etc.
A: Actually the stock cam options for the standard 400 on 1968 birds was the 067(400 std AT and manual), 068(RA-I AT; 400HO manual), 744 (RAI-4speed) and 041 (RA II AT and manual)
Side Notes: 066 was only used on standard 1967 auto 400 firebirds. 400 std autos were ‘upgraded’ to the 067 cam in 1968. Interestingly, the 400 HO auto cars did not receive the cam upgrade (to 068) that the 400 HO manual cars received. Instead the auto 400 HO cars used the stock 067 cam in 1968. Also of interest, the RA I auto cars were ‘downgraded’ to use the 068 cam (vs the hotter 744 cam used on RA I auto birds in 1967).
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Content last modified: January 16, 2014 at 8:49 am
Q: Heads (061’s) for 1967
Anyone know what kind of compression bone stock 1967 061 400 heads will give me?? iam getting conflicting information about them, some say they are open chamberd and other are saying there not.
A: The 1967 061’s are indeed an open chamber head, they are the original put out as sort of a prototype, and they are unlike any before or since. The chamber is very open, but the chamber measures out to about 72 cc’s… It also has 2.11 int and 1.77 ex valves…. The down side is that it has press in studs which aren’t as reliable, but you can convert them cheap, relatively. These are probably the cleanest chambered head… I asked George Hanks about this set of heads, who has personally worked with these… he said
” the #061, used on grocery getter 400s in 1967. I’m convinced that this head was the prototype for the later production open chamber heads, but the Pontiac engineers learned something on this head that they incorporated into all of the round port performance heads of the RA-II, IV, HO, and SD-455 heads. While the 061 still has the A.I.R. bosses in the exhaust ports, the chamber is the most open of any of the production heads. There is almost no ridge across the chamber, as two separate cuts were used during the machining process, and the spark plug hole is located in the highest possible portion of the chamber. In addition, the rear or squish wall of the chamber is laid back to a 60 degree angle, producing a true polyspherical chamber, with an absolute minimum of squish area. These heads have been ignored for years, primarily because they did not fit into any of the NHRA performance engines, and they had pressed in rocker studs. The A.I.R. bosses clog up the exhaust ports, and within the old non-porting rules of NHRA, nobody cared, but with some porting and screw-in studs, this head will knock your socks off. It doesn’t flow any better than any other D-port head, but the conversion of fuel to cylinder pressure is just as good as the RA-IV heads.”
If you get a copy of Pontiac Musclecar Performance 1955-1979 by McCarthy, it will tell you about these heads, good reference for part numbers, heads blocks, etc… 061’s are also mentioned in the H.O. specialties book, “Pontiac High performance Engine design and Blueprint assembly”… That head should give you compression in the realm of 9.8-10.1 with stock pistons… I’d love to have a set of them…. I’ve been looking for those for about a year now..
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Content last modified: January 16, 2014 at 8:50 am
Q: 670 Heads
Should I use my 670 heads or switch to something else. I have heard the 670 are closed chamber heads and the valves are shrouded. You would do better with some 62,16,12,13, or 48’s.
A: While you are right about the shrouded valves, I find it interesting that Pete McCarthy writes the following in his “Pontiac Racer’s & High Performance Handbook”:
“The 670 heads are unique in a number of ways:
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I was and is the only late closed chamber design.
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The intake port is the best flowing of any production head including the Ram-Air IV.
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It is the only big valve head with exhaust port air injection holes, although a number if Eastern cars didn’t have them.
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It was the first in a long line of high performance Pontiac heads with screw-in studs and stamped steel pushrod guide plates.
If one obtains these 670 heads, and opens the chambers ala the 1968 and later 400-428 heads, and adds the good valve prings, you will have as good a high compression head as is possible to find. The 670 head is one of the great junkyard buys available.
That’s pretty impressive. I imagine that the removal of the material shrouding the valves, plus enlarging the chamber to match the better quench area of the 1968 and later heads, one would also shave a couple 10ths off the compression ratio, ending up somewhere in the are of 9.75 or 9.5 to 1. Remember that Pontiac overestimated compression, so a rated 10.5 to 1 was closer to 10 to 1.
If you were looking for a decent head to use without modifications, and found the 670s at a good price, they are worth buying. If you were interested in making the above modifications, you would end up with dynamite heads.
By chance, the 1968 YS block (GTO/big car) in my car came with these heads. After reading McCarthy’s comments, I decided to hang on to them.
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Content last modified: January 16, 2014 at 1:16 pm
Q: Speedo Cable Mystery for 1968
During the course of researching codes for the 1968 Firebird Body Broadcast Sheet, I’ve discovered some mysteries one of which has to do with the Speedo- Cable. I have heard it said that the 1968 Ram Air Firebird used a special, unique Speedo-Cable (per Jim Mattison) but so far, no one (incl. him) has been able to produce and factory documentation proving this. The only proof has been in the Parts Book and that only says the Automatic cars used a special Speedo-Cable.
The other issue is the Two-Piece Speedo Cable and the use of a Speedo-Gear Adaptor. What I’d like to know is which Firebirds used the Two-Piece Speedo Cable and what exactly was a Speedo-Gear Adaptor ? I know it was optional and it even had a sales code (#591) but what required it ?? So, if you have anything to add to this issue, please jump in. I’ll post another message with part numbers for those interested in further details of this mystery.
A: Know the answer? Send the answer to me on this issue.
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Content last modified: January 16, 2014 at 1:17 pm
Q: Speedo Cable
Anyone knew how to disassemble the 1968 AT cable from the casing. I’ve tried pulling the cable out from the speedometer head side but no luck. Does it come out from the transmission side?
A: My Speedo cable broke a couple of years ago and I pulled it out from the top behind the cluster. I didn’t move the casing of course, just the cable. I also reinstalled a new replacement cable thru the cluster top down to the trans. (Also make sure you oil or grease the cable for smooth gage readings.)
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Content last modified: January 16, 2014 at 1:18 pm
Q: Speedo Cable Lubrication
Does anyone of you guys know how to fix my nervous speedo dial? Driving slow or fast doesn’t matter I can’t get a steady reading.
A: Many times nervous needle is caused by a dry speedometer cable. Try pulling and lubing the inner cable with quality speedo lube and reinstalling. This has fixed my needle problems on 3 different cars. Just looking at a part of a restoration that is sometimes overlooked, and a cable breaking because it is dry is no fun either.
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Content last modified: January 16, 2014 at 1:19 pm
Q: Backfiring Problem
I have a 1968 Firebird with a built 73 Pontiac 350 and an electric choke. The last two mornings on the first start it has backfired. I’m a pretty weak mechanic…as you can tell. What should I do.
A: I’d start with the choke. See if the is sticking and flooding. Also, check the timing. When was your last tune-up?
A: Your problem could still be in your choke. Is it backfiring through the carb or exhaust? If through the carb, most likely you have a lean situation that could be caused by your choke not closing fully. This would explain why it goes away when it warms up. If it is your exhaust, that’s another story and most likely would involve timing or a sticky exhaust valve.
The first thing I would do is check the position of the choke when cold. Before you start your car, remove the breather and open the throttle to allow the choke to close. If it doesn’t snap closed fully, there’s your problem. Check to see if you can close the choke all the way (there should be a slight opening about 1/8th to 1/4 inch when fully closed) by pressing it closed. If this is the case, buy a can of spray carb cleaner and hose the linkage. If the problems persist, you’ll probably have to grab a buddy (or mechanic) who know a little more about old cars and get him to help.
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Content last modified: January 16, 2014 at 1:20 pm
Q: California AIR System
I have a 1967 firebird with a 326ci with a 4 bbl carter carb and it had factory air. the car has a smog pump which i tried removing but the heads had holes in them that had hoses coming out and joining to some sort of object in the middle then in turn connected to the smog pump which had a hose connecting to the air filter. i tried plugging the holes in the heads but the engine would just starve for air when i tried turning the car on, and it would make a weird popping noise when i kept them unplugged could anybody help me with these problems?
A: Concerning your AIR pump. First off, let me start out by saying that the AIR system you are refering to came on California Firebirds only, and is somewhat rare. If you plan to remove it, keep it intact, and that includes the vent tube from the right rocker to the air cleaner, and the air cleaner as well. (If you are just going to toss it, let me know and I’ll purchase it from you at a fair price.) You can remove the AIR system from your car and run without it. All Pontiac heads from 1967 have the holes in the heads that you are refering to. Non-AIR equiped cars have ‘plugs” which are screwed into the heads. Remove the AIR pump and associated plumbing. Screw in the plugs into both heads, and plug the the inlet on the underside of the air cleaner. That’s it. If the engine was starving for air, it wasn’t because you plugged the AIR ports in the heads. Look for another problem. The AIR system is masking it.
Key Words: AIR, A.I.R., emissions, CARB, Air Injector Reactor
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Content last modified: January 18, 2014 at 11:25 pm
Q: Runs Great then Quits
My problem is my 1968 – 350 runs great in the garage but stops on me under power or extended road work. It can go for days without shutting down and then when I think the problems solved, wham! The motor will sometimes start right back up (sometimes rolling in neutral) or I may have to wait five to twenty minutes. This has been happening for six weeks. I have tested or replaced the following.
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Fuel pump, flex lines, Carb. Note: No residue in carb fuel line filter
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Complete tune-up with points, condenser, rotor, cap, wires & coil.
Note: Dwell & timing stay perfect. Anyone out there with an idea.
A: It sounds like you’ve been guessing instead of diagnosing. The next time it quits and stays dead, check for fuel and ignition. If fuel, it may be vapor locking in the steel line, or a fuel pump that’s weak. Could also be a problem with the tank, maybe there’s not enough venting, causing the tank to have a vacuum in it preventing the fuel pressure from being maintained. Ignition is likely to be a bit easier to troubleshoot, unless it’s something weird like a loose wire in the ignition circuit or such.
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Content last modified: January 16, 2014 at 1:40 pm
Q: Severe Miss When Cold
I’m trying to track down a miss during warm up on my bird. In the past, I could start the car when cold and drive away, it would run fine. I’ve noticed a miss that has progressively gotten worse after each day, spanning over the past months. I’ve replaced the distributor cap, rotor, plugs and points but no change. The car starts fine, but it randomly misses, getting better when it warms up. Once at operating temp, it seems to run fine but you can hear it miss a little randomly. Under heavy acceleration there is no stalling of performance, hot or cold. I doubt it’s the carburetor (Edlebrock 650) because the car seems to run fine after warm-up, just a random miss.
One thing. The timing is set really advanced, about 14 degrees BTC. I’ve been running it that way for a number of years. If I set it to 9 degrees there is no power. Also, the manifold vacuum is 18 and steady when hot.
Any tips on what to look for would be helpful.
A: check for vacuum leaks check or replace plug wires replace fuel filter
A: I suspect you don’t have enough choke action. Either insufficient spring tension, sticky linkage, or too much choke pull-off. Generally lean when cold. If you set the timing back it would probably pop back through the carb with all else the same indicating it’s lean.
A: Change the plug wires. The wires are more than likey breaking down when cold since more current is needed then. A good set of Delco wires should do the trick.
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Content last modified: January 16, 2014 at 1:41 pm
Q: 350 H.O. Components
What components were used on a 350 HO that made it special from a regular 350?
A:
- TH400 –
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Definitely used on 350HO but TH350 on std 350 engines (if ordered with Turbo Hydramatic)
- Carb –
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7029268 is correct. I bought the same one when I needed a carb.
- Suspension –
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It sounds like you have air shocks. And I don’t think they were used, even in the heavy duty suspension. I looked at the AMA spec (https://FirstGenFirebird.org/firebird/1969/ama/ama_page9.html) and it never mentions air shocks. Probably a previous owner put them on???
- Manifolds –
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I e-mailed Paul Spotts (formerly of Performance Years) and asked him and he too says they used STD manifolds. The casting number I gave you was from the ones on my wife’s car. I was told that they were from 1969-1972 full size car manifolds, based on a “Foundry Parts List”. Sounds like, from your casting dates, that they are correct. Good for you! Oh, one last check might be to see you if you the oil filter adapter that would have to be used if you had the long branch, since they interfere with the normal oil filter location.
- Heads –
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I also asked Paul about this, and he said that they were in fact different for the 350, but that some 400’s (like Judges other Hi-Po cars) may have gotten the 350 #48 heads for even more compression, because of the low demand for the 350HO, and thus having extra parts around the factory.
- Valve Reliefs –
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The 350 HO cars must have had the valve reliefs since the size of the valves, even if they were right next to each other (2.11+1.77=3.88) is larger than the bore of 3.875 (.) But recently I heard it suggested that maybe all 350’s got the valve reliefs so they didn’t have to cast and stock two different type of blocks. Plus I know of people who have put the Large Valve heads on their 1969 350 2-bbl blocks and did not crash the valves, so the must have had the valve reliefs.
- Power Steering Loop –
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Asked Paul about this too. His recollection was that is was used on cars with high numeric gear ratios, like 3.73 or higher, or 3.90 or higher, since they would typically be revving higher, thus spinning the pump faster. What is the rear end gear ratio on your car?
- Cam –
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I’ve only heard lately the story that they used the 744 cam in 350HO cars, but that’s not what the AMA spec says or any other literature I have. 067 cam for Auto, 068 for std trans.
- “Hood Scoop” –
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I noticed this passenger side “hood scoop” that looks like a hood tach on some factory literature too, which also shows it on a lemans. Was supposed to be used for cold air induction. Maybe this falls in with the long branch manifolds….planned but never put into production????
- Side Notes –
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From the picture you sent, I noticed that you still have thermostatic vacumm switch on the intake. That’s good news, I almost never see a car that still has this, the manifold is usually plugged. Also noticed that you are missing the second alternator bracket that seems to duplicate the one from the water pump, but attaches to the front bolt on the thermostat housing.
If you want some info on my wife’s car, go to:
http://www.angelfire.com/on/geebjen/jensbird.html
There is only one picture of the engine compartment there, and it was taken by the previous owner. Since then, I’ve gone to std black plug wires, painted the intake, valley pan, valve covers, brackets, water pump etc, and will be replacing the chrome air cleaner with a factory single snorkel with black lid and pcv vent tube etc. I’m hoping to get some newer pictures of the updated engine compartment soon. When I do, I’ll post them on the site.
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Content last modified: January 16, 2014 at 2:12 pm
Q: Verify a 350 H.O.
Up until about 5 minutes ago I thought my bird was originally an inline 6. Well I now know it was a V-8 after checking the VIN. Is there anyway to tell if it could have been a H.O. through the vin and trim or would I have to go through PHS?
Could I tell from strips, engine code, hood holes, tires, or other distinct H.O. markings?
A: As far as I can tell, the only 350HO info on the car would have been atttached to the engine – such as code WK (manual trans) with cam 067, carb 7028269 and distributor 1111447 or YM (automatic) with cam 066, carb 7028266 and distributor 1111282, both with casting number 18 heads.
Checking for other options is a more questionable. Since the 2 barrel 350 could have optional dual exhausts, evidence of that option is not a guide either. Both the 350HO and the 2 barrel had the same hood emblems and related holes, so this is useless info. The stripes could have been a option deleted.
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Content last modified: January 16, 2014 at 2:14 pm
Q: Starting Problem (Bypass Solenoid)
Tip for bypassing the solenoid if will not start but still have power.
A: I was stranded last night for 3 hours because my car wouldn’t start. I had power so I figured its the solenoid. Finally a good old boy stopped and showed me how to bypass the solenoid with a screwdriver. All he did was lay it across the positive battery cable post on the solenoid terminal post and the closest terminal (drivers side)and I cranked it at the same time and it started right up! This takes 2 people as one is under the car and the other inside. I drove home no problem and right away jacked the car up and dropped the starter.
A: You don’t need 2 people, just turn the ignition to the run position and get under there with your screwdriver it will start.
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Content last modified: January 16, 2014 at 2:25 pm
Q: Starting Problem
What could cause a car to not start when turning the key results in absolutely nothing. No clicks, nothing. Charging system works, battery has juice ( at least to operate lights, etc.). I went out over the weekend and it started fine. Drove it, stopped, and when I tried to start it again, nothing. Got a jump and it started. Since then, it started every time just fine.
A: I had a starting problem that was really intermittent at one time. Turns out the nuetral safety switch (term?) on the transmission (67 400 w/ TH400) was not hooked up correctly or loose, and I would have to shift into park, then re-shift into park to get it to start. Same as you, no clicks or anything, but the rest of the electricals worked fine.
A: For that kind of no-start, it may be a “dead” spot on the starter, usually caused by a dirty commutator/brush contact. Next time, give the starter housing a tap with a hammer while somebody turns the key – if it starts then, replace the starter. Another case may be a loose cable connection at battery or starter, even though it feels tight, it may need to be a bit more secure. If a dead spot, you just got lucky while the jumper cables were connected.
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Content last modified: January 16, 2014 at 2:26 pm
Q: Determining Correct Plug Gap
For those of you who made the conversion from the stock heads to a set of 6x’s – What plug gap do you use now?? Since GM went to the HEI when these heads were used, I would guess that the plug gap should be .055 – .060″[?].
A: You gap the plugs to correspond with the ignition you are using, not the head castings. If were running a points distributor, you gap the plugs according to the typical points gap of .040. If HEI, use the HEI .055 gap.
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Content last modified: January 16, 2014 at 2:26 pm
Q: Electronic Ignition (HEI)
I’m open for advice on this one. I’m considering changing over my 69 Firebird 350 to Electronic Ignition. The car is used mostly for crusin with no strip action. Think this is a good idea? Where is a good place to get the parts needed for conversion?
A: The cheapest by far is to convert it to HEI. You can pick one of these up at a salvage yard for about $10. If you decide to do this, you’ll need to run a 12 volt wire to the distributer (the existing wire is a resistor type and will only supply about 6-8 volts).
One trick I did so I could change it back later (for show purposes) is I traced the wire back to the firewall connecting block and soldered a #16 wire to the same terminal (This parallel the two wires. I then taped the new wire to the harness and taped up the old wire there it comes out of the harness. Looks clean and there’s no hacking involved.
Another would be to buy a kit to convert your points to electronic breakerless ignition. Check the ads in the back of Car Craft, Kit Car, etc. or contact you local speed shop.
A: I got mine of a 400 firebird in the junk yard. It bolted right on. Make sure you get the little wire clip that connects to the distributor or you will be going back. Also check to make sure you do not have a resistor wire going to it. The + side of the distributor should connect to +12 volts that goes on and off with the ignition key.
A: The fit of the HEI is close but it worked on both my 350 and 400 (same block). You may have to rotate the oil pump keyway (stick a long common screwdriver into the distributor hole) to get the HEI in the approximate location as you’ll only have about 20 degrees of rotation. If it still doesn’t fit, check to make sure the transmission and motor mounts are in the correct location. The other problem could be position of the sub-frame relative to the body. If everything is pushed back for tight body seams you could run into clearance problems.
A: The GM HEI will NOT fit. The firewall is too close. You can install the distributer, but the cap will not go on. Another option is the Mallory Unilite. I installed this on my 69. So far I like it. The cap is red, other than that it looks stock, and you have a choice of vacuum or mechanical advance. Most of the Performance catalogs list them. Good luck!
A: The HEIs are virtually maintenance free. Stock and performance parts are cheep and easy to find. They outperform stock breaker point distributors in all areas. Unless you are running some serious compression ratios or are going to be drag racing and consistently revving your motor above 7500 RPM, the HEI will serve all your spark needs.
A: The guy that rebuilt the 400 in my 1967 replaced the stock distributor with an HEI unit. No modification to the firewall was necessary, but there certainly isn’t the room around the distributor like there was with the original unit. I’m into originality and as a rule don’t think that aftermarket parts are up to the engineering standards or quality of genuine GM parts. (Please no flames!) So the HEI distributor is a nice compromise.
I’ve been driving 1967 400 firebirds since 1979 and I have to tell you the performance with the HEI is much better than the breaker/points unit. The advantages of using the HEI unit that I’ve seen are: the spark plugs don’t foul out anymore, the car cold starts much easier, and I’m not forever messing with dwell settings. My ignition system used to always be a concern, but it is not anymore.
The only disadvantage I see is for us purists. Like I said before, it’s hard to get use to seeing that big distributor in the back of the engine where a little on used to be. If you plan on driving the car a lot, do it. If you plan on showing the car, don’t.
A: I’ve been very happy with the HEI system in my 1968 Firebird 400. The maintenence can’t be easier, just replace the cap and distributor every once in a while, and do a recurve every once in a while. No need to have to deal with gapping the points every other month, or having to adjust the dwell. You can also run a gap of .060.
I can’t be happier with the HEI setup in my ‘bird. The only disadvantage is that GM HEI distributors are known to drop a lot of current above 4600 rpm so if you’re running at high revs, you may want to get an aftermarket HEI style distributor.
A: put in an acell electronic. they are trouble free. mine is 5 years old and never been touched!! it fits the firewall and 14″ air cleaner great.
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Content last modified: January 16, 2014 at 2:27 pm
Q: Electronic Ignition (HEI): Revisited
i have a 1967 firebird with a 326ci it has a 4 bbl carter carb and it had factory air but i took it out cause it didn’t work at all and had no hope off fixing. anyway i called a couple of places cause i wanted to drop an electronic distributor in it, but a couple of places said it couldn’t be done, that i would have to put an ignitor in my old distributor to convert it, is this true if not what other stock gm electric distributors would work in it (off what other cars?)
A: Concerning the electonic distributor issue, you have many options to choose from. First, just about any Pontiac late model HEI distrubotor will work in your engine. My 400 currently has an HEI distrubtor from a 1977 TA. Works great. The second option is a points replacement kit. This replaces the only points and condensor in your current distributor with and electonic unit. Both Mallory and Accel offer these units. Your third option is to replace the entire distributor with an after market electronic distributor unit. Once again, Mallory and Accel have excellent units for the Pontiac motors.
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Content last modified: January 16, 2014 at 2:28 pm
Q: HEI Distributor (Revisited Again)
I’m thinking of getting a HEI-distributor for my 1968 bird. But I wonder, will the larger distributor require body modification? I’ve heard so much good about the HEI so I’d like to give it a try in order to save some gas. (Could you imagine living in a country where you have to pay almost 4 dollars/gallon??) And if body mods will be needed and before I go crazy with my big sturdy hammer, whats behind the firewall? …anything fragile?
A: I swapped to HEI on both my 1967 and 1969 Firebirds. On the 1969 I had to pound the firewall in about 1/4″ to 1/2″ to make room for the Accel Supercoil I added to the HEI. On the 1967 no modifications were required. The best way to modify the firewall is to use a big splitting mall or big hammer when the engine is out of the car. If you’re careful how you do this it’s hardly noticable after you have installed the HEI. Good Luck,
A: If your body bushings and subframe position is all good there should be just enough room for the HEI. Before you go pounding on the firewall, check the bushings.
A: I have a 1968 400 and HEI fit with no modification…
A: I installed an HEI in my Bonneville. I just bought a new unit from a local shop that had a distributor machine. They set it up and I installed it. Simple.
My Firebird was missing the original dist. and had an Accel dual point completely worn out POS. But, there was not enough room for the cap to clear the firewall on my bird. Before you invest in an HEI, make sure you have the room! Some birds do some don’t (borrow one, drop it in, then install the cap). You can take a block of wood and a hammer to make room on the firewall too. I didn’t like this idea.
If the HEI fits, it’s pretty straight forward to install. You will need to re-gap the plugs (.045 ?), and new thicker wires are a good idea too. In fact, I think you will need them to attach to the new style cap.
Grease: yeah you need to grease ’em up. A new unit comes with it. If you go the used route, just get some di-electric grease. The HEI units have a coil built into them.
Also, and I don’t remember why, but stay away from the Accel clone (anyone know why I’m saying this?) Get the genuine article. It was worth a few extra bucks to me to buy the new unit from GM. By the time you rebuild a used unit with the usual components they need, you have a lot of your resources invested. New stuff is so clean too.
For my Firebird I settled for the Mallory Uni-light with mechanical advance for added simplicity ( I have a 4 speed). I think you have more options to trick these out than the HEI. Besides, that red cap is prettier (here come the flames).
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Content last modified: January 16, 2014 at 2:29 pm
Q: Firewall Gloss Level
What is the correct gloss level for the Firewall.
A: I sent an E-Mail to Jim Mattison regarding gloss level on the firewall since the High Performance Pontiac articles were unclear. Here is the response he sent me…..
Thanks for the kind words on my 1967 Ram Air Firebird. The car looks much better in person than it does in the magazine.
To answer your question concerning engine compartment detailing, the gloss level on the firewall area is a 85% black.
I hope that this information is helpful!
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Content last modified: January 19, 2014 at 3:17 pm
Q: HEI Upgrade
Thanks for all the input. What I’ve read is that the increased efficiency of electronic ignition will enable the end gases to burn normally, rather than contribute to knock. It seems to me that to reduce knock, I’d have to replace the coil and wires, and regap the plugs, along with replacing the points and/or the whole distributor. Can anyone confirm that knock was reduced/eliminated by installing HEI, or am I setting myself up for disappointment?
A: Installing an HEI is unlikely to reduce/eliminate a knock problem other than by coincedence.The advance curve(s) are what will make the difference.If the HEI you install happens to have a minimal amount of centrifugal advance and/or a vacuum advance unit with a stiffer spring than the original unit then knocking will be reduced. Also the vacuum advance units have differing amounts (in degrees) of advance.
If your only complaint with your points distributor is the knocking problem then you may want to check its advance operation and correct/modify as required.It is not difficult to do but requires some amount of know-how and a few tools such as a accurate tachometer and a timing light (dial-back type) and a dwell meter.For starters make sure the dwell is set correctly and the initial timing is set to spec.Then with the engine warm increase the engine speed while watching the timing mark,when it stops moving as the engine speed increases further dial back the timing light (obviously you will find it easier if a friend works the throttle while you watch and manipulate the timing light) until the mark lines up with the TDC mark on the timing cover.Now read the dial (or display if you are using a digital) on the timing light,this is your TOTAL mechanical (or centrifugal) advance.It should be around 30-36 degrees.
At this point (if the numbers are O.K.) you might try disconnecting (and plugging) the vacuum advance hose,then drive the car and see if the pinging is gone.Be sure and try both hard full blast runs as well as light throttle/lower rpm/higher load situations.If the car works O.K. then you may concentrate your efforts on the vacuum advance.There are a number of ways to go about this including:replace with different unit with less advance and/or stiffer spring,replace with adjustable aftermarket unit or modify your existing unit.By the way,most units have the amount (in degrees) of advance stamped on them (usually 10,15, or 20).You could of course,leave it disconnected but fuel economy and throttle response will suffer.Sorry I’ve been so long-winded about this, of course there are other things to consider like engine temp,combustion chamber deposits,fuel/air mixture.I hope this helps,feel free to email me privately if you have any questions.I don’t have all the answers but I may be able to help.
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Content last modified: January 16, 2014 at 2:30 pm
Q: HEI Fit
I am about to throw the engine back into my 1969 bird and thought I’d go ahead and replace the distributor with an HEI unit. As the clearance is so tight to the firewall will any poncho distributor fit or do I have to get the “small cap” one?
A: I’m not aware of any small cap versions that fit a Pontiac block. Installing an HEI in a Firebird is a little of a crap-shoot. Some owners report that they had to “clearance” there firewall with a BFH before the HEI would fit. Others, including myself (in a previous coupe), didn’t have any problems.
The difference may be in the condition of the bushings and sub-frame. When I pulled the sub-frame out of my convertible, the mounting pads that are welded to the sub-frame (which bolts to the base of the firewall), had a hole about as big as the bushing itself. I have serious reservations that an HEI on this car without extensive repair or modifications.
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Content last modified: January 16, 2014 at 2:31 pm
Q: OHC Meaning
I keep reading OHC for engine descriptions. What does this mean?
A: OHC – Over Head Cam which correlated with the 6-cylinder.
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Content last modified: January 16, 2014 at 2:55 pm
Q: OHC-6 Buildup
I am starting to get ready to rebuild my “rebuilt” (so said the previous owner) OHC-6. I know some of the problems these engines have with oil and wiping out camshafts, but I was wondering while I have the block torn apart, are there any special machining operations I should have done? I am concerned about the cam bearings, since I have already lost a few 1-bbl cams (or actually have housings from wiped out cams).
The combination that I am planning on running is:
– 1968 1-bbl head (9.5:1 Compression ratio) fully machined with new valves and springs (single)
– 196? Block (I plan on putting in new bearings and rings, pistons if needed)
– 1968 Sprint Cam (found NOS from Internet… long story)
I plan on getting new oil pump gears and a new timing belt as well. With a lot of money involved in this engine, I would like to make sure it will last. I am planning on pulling the engine out in the next few weeks, and would like to be finished for next spring. I have put 25 miles on the car this year, due to moving and other projects (1968 Catalina).
I also have two other questions:
Where did you get your exhaust made? Do they have a pattern for it? I have asked several “custom” exhaust shops about doing this and they have all said it cannot be done. I saw it done on the Fitchbird, and personally I want the splitter exhaust tips.
AC was not available on the Sprint? Why was this? My car is originally a 1-bbl, but came with AC. I am making this into my dream Sprint (does this answer your question on options?), and will keep my AC. I am just curious about not having it available and the why.
A: I ll try and answer a few questions on the OHC rebuild. A properly built motor will not wipe out cams. Especially with todays super lubricants. The cam housing is made of aluminum and has no replaceable bearings.
It is important to pay close attention to the upper oiling system as this is what I see screwed up the most. Next is to pay attention to the valve setup. DO NOT tip the valves. You will get interference between the follower and valve spring retainer. Lash adjusters will compensate for the change in stem height. I will say this again… get a factory service manual… In the case of the OHC-6 get a 67 manual as well as the year of car you have. The 1967 manual has more OHC-6 info than any other year.You will need the year of manual for your car because they made some changes over the 4 yrs of producing this engine.
If your year is 1967 (you didnt state) then you save money on manuals.67 Firebird Sprints were avaliable with factory a/c as was the Tempest /LeMans Sprint for 66-7. However in 68-9 it wasnt avaliable as an option for any Sprints. Reasons are not clear but I suspect the following: compressors were dying right and left on these engines (try and engage a a/c compressor clutch at 6500 rpm and see what it does.) sales of the a/c equipted Sprints were very low (i know of only a handful and 2 are here), Like the R/As Sprints were built for the hot rodder who didnt neccessarily want extra baggage.
You can successfully convert a 1bbl car to a Sprint and retain the a/c but there are some parts that are peculiar to the a/c equipted Sprints. As for the duals on a Sprint Glenn took a little different approach than i did. I personally think that his is too loud the way its done and he uses tailpipe extensions that protrude beyond the bumper to help with the cabin noise level. The approach I used for a dual conversion is this. Buy over the counter dual exhaust for the V-8. get the crossover muffler and the front resonators dont buy the front pipes for the V-8.
Use V-8 tailpipes(here comes the dual splitters you wanted) install all of this on the car with proper dual exhaust hangers drive it to a muffler shop that can custom bend pipe and have them make the front two pipes (maximum size of 1-7/8 in dia) to make up to the front resonators.this system is large enough for the Sprint but isnt terribly loud.
We have experimented with just resonators or just the cross flow muffler, and they are both too loud. You can subsitute small mufflers in place of the resonators if you want to further quiet down the system. If you are going to run single valve springs make sure they are to the same specs as the DUAL springs that the Sprint had. With the 1bbl head and valves you are pushing it as far as lift and coil bind on a 4bbl cam.
You didnt say what combo block ,crank and pistons you will use but its good to keep the CR just under 10:1 for the street. However if you increase the CR to 11:1 or higher it really wakes this motor up. I have tried about every combo of head ,cam,crank,pistons and find that the 68-9 4bbl head is best on the 230 If overbored.But a killer combo is the other way around and use a 66-7 4bbl head on a 68-9 short block. Hope this helps
A: Reagarding the exhaust, I had a friend who worked in a shop with a bender, and he still had the pattern cards for 1967, 1968, and 1969 Firebirds, we copied the factory axle tubes, but with 2-1/4″ pipe. We used resonators with 2-1/4″ inlets and outlets, same for the muffler and for the tailpipes. (Remember my muffler went away with the rear suspension mods.) We made 2 engine pipes from 2″ stock, the manifold outlet for cylinders 1-2-3 went to the left resonator, with most bends resembling the factory 1-barrel pipe, then the manifold outlet for 4-5-6 had the pipe make an S-turn under the transmission crossmember to connect to the right resonator. Both pipes needed to be enlarged at that point to fit into the 2-1/4″ resonator. It is not difficult for a pipe man with a BRAIN!
On the engine, there are NO cam bearings! The cam rides right on the surface of the housing, and I’ve never seen a housing wear out, even after 200,000 miles or more! You need to make sure the oil restrictor in the head is not damaged, so you get the right amount of oil pressure and volume to the top of the engine. Also, the height of the valve stems is critical on this engine, I think Gary has a spec on that. Many machinists grind off some valve stem after grinding the valve face and seat, and do this to compensate, but most never measure it, they just guess how much, Also, there are differing valve lengths depending on the chamber size, so you can’t mix and match from different heads unless they are same application. The block is the simplest one on the planet, it holds crank and pistons, and the oil pick-up tube, everything else was on the accessory drive housing or on the head!
Let me know what your plans are regarding cam followers, there’s some stuff to beware of.
A: is right on the valves. I had two heads done and both times the supposed machinist ( owner’s brother ) ground the tops down by eye. You could look down the row of valves and see that they all were different lengths. According to a good source the following are the lengths:
66 1bbl 4.9 67 1 bbl 4.9 67 4 bbl 4.99 68 1 bbl 4.8 68 4 bbl 4.9 69 1 bbl 4.8 69 4 bbl 4.9
I am sure someone will correct me if these are wrong. If you have someone do your head, make sure they know that the clearance is critical. I guess the SOB that ruined both of my heads thought he was working on a tractor. The valves were so far off that the cam cover would push up during preliminary testing.
A: the weird pipe is the Y-pipe from the dual outlet manifold that the factory used on all Sprints.
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Content last modified: January 16, 2014 at 2:57 pm
Q: OHC Conversion to V-8
OK gang I really need some help here. I’ve been looking for a 1968 convertible 400 car for about a year now, however I’ve not been satisfied with the condition/options of the cars for the $. Consequently I’ve entertained the idea of just building my own. I am somewhat of a purist so I don’t want to screw up a nice/clean original example. So I found a reasonably clean six cylinder convertible, non matching #’s OHC six. It does have a four barrel, but its not a SPRINT option, 3 speed manual on the floor. No PS, PB, manual top. I’m planning on building the car and keeping it forever, so I will not try to pass it off on anyone else. Here’s what I want to do/ am consiereing. 400 or 455, streetable that will run mid to low 13’s. Engine cam intake carb ect I’m fine with questions I have are: Will the existing 3speed work with either engine?(I am not a total idiot but just figured I’d ask) if not which manual trans, should I use? Where to find and how much? I haven’t ruled out going to a 4speed auto( like the one in HPP 1967 Goat) opinions on this welcome if anyone has tired it. IT has manual drum brakes(recently rebuilt/lines cylinder ect works great) are they sufficient or will I need to upgrade to account for extra weight of V8 trannie ect. Suspension: new front/rear springs? I know some guys like 6 cylinder springs for weight transfer. Suggestions? Or other issues I have not considered any and all advice is greatly appreciated.
A: You asked earlier about converting to a V-8 and stick. There are differences in the clutch setup between the OHC-6 and a V-8. The z-bar is longer on the OHC-6 since the block is narrower. Also a OHC-6 runs much better with the correct 4-speed, which will not last long with a V-8. They originally came with a Saginaw with a 3.11:1 first gear ratio. Most Muncies used a 2.55:1 first ratio. Going to a steeper rear will work well with both engines. The OHC-6 will rev higher, but it stops making real power around 4500 RPM.
A: I can tell you the transmission behind a six is a Saginaw 3-speed, very light-duty, not likely to hold up behind ANY V8! Also, the OHC6 has a different bell housing and probably different Z-bar than the V8 applications, so to do a 4-speed, you will need a Muncie to be period correct, or a Borg-Warner T-10 (I think the T-10 may be a little stronger), and most of the rest of a 4-speed change-over. The 700R4 Automatic is a good transmission, but only comes in a Chevy bellhousing pattern. The 200-4R is run behind VERY hot V6 Buicks in drag racing, but you’ll have to do some research to see how they do that, it does come with a dual-pattern bell housing. The 200-4R also fits better, Gary installed one in his 1967 Tempest Sprint with no chassis mods, just moved the crossmember back to an existing set of holes in the frame. There are no additional holes in the ‘bird, but it is still likely to be easier to make a 200-4R fit than a 700R4. The driveshaft even stayed the same in the Tempest!
Also, although drum brakes are, shall we say, adequate, there may come a time when you need MORE than adequate! You will NEVER regret changing to disc brakes! Especially after going through a puddle and having NOTHING! You’d have to be a bit of a daredevil to have drum brakes in a car capable of turning low 13’s!
By the way, I would probably be interested in aquiring the bell housing and Z-bar from your OHC6 after you remove them, as well as the flywheel, and any other six-specific related clutch parts.
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Content last modified: January 16, 2014 at 2:59 pm
Q: Rebirth of OHC-6
I have a 1968 Firebird with a 250 O/H cam 1bbl carb. And am having some serious running problems, so am considering dropping the 400 pontiac engine I have (from a newer Firebird) into it. Will a 400 bolt up to 250’s stock tranny which I believe to be Pontiac’s 2-speed (automatic, no a/c) or maybe powerglide.(Did Pontiac put Powerglide’s in, in 68?
A: Tom Can I ask why you want to change the motor if the OHC-6 is repairable? You have alot of other things to consider when doing this swap such as,motor mounts,tranny cooler,larger radiator,rewire the engine section of harness, cooling baffles around the radiator. An a/c equipted car is easier to change as it comes with these baffles regardless of the orginal power train. Not enough of the OHC-6s left… This motor basicly revolutionized the industry as it is the basis of most OHC-6s(4 and 6cyl) today.
A: Fixing of Problem
————————
I would suggest first looking at the carb. The carb setup sometimes causes a vacuum leak towards the cam cover, due to the stud being difficult to reach. The idea of a steel gasket would solve this problem. The second area that I would look at would be the vacuum advance on the distributor. If it gets gummed up, it won’t release correctly. Just some ideas.
I don’t have the carb numbers with me, but I will try and get them for you. There were I believe four different carbs used: automatic, automatic with air, manual, and manual with air. The air condition carbs used a solenoid to adjust the idle while the air was on. If you need a carb, myself and several others on this list have a bunch laying around.
History of Engine
———————–
The OHC-6 engine is often misunderstood. The belt was the part that worried most new car buyers between 1966 and 1969. Unfortunately, the belt holds up very well, it is the oiling system that needs work. Oil starvation of the top end (i.e. camshaft) causes many camshafts to be wiped out. The engine came in two versions, a 1-bbl base engine with a 9.5:1 compression ratio and a 4-bbl “Sprint” version. The Sprint version included a 10.5:1 compression ratio (determined by the cylinder head), dual valve springs, a 4-bbl Quadrajet (the first production use of this carb), a high-lift camshaft, and dual exhaust manifolds. The Sprint version was rated at 215-230 HP depending on the year. The engine was 3.8 litres (230 CID) in 66-67, and 4.1 litres (250 CID) in 68-69. The best engines to build up are the 1968 blocks.
Hot-Rodding
—————–
Most OHC-6’s that are still around are 1-bbl automatics. I believe this is due to the fact that these cars were not beat on as much as the 4-bbl/manual transmission versions. With an advertised redline of 6500 RPM, the manual versions tended to be abused and have the oil problem noted above. The ideal engine to build with today’s gas is a 1968 block with a 9.5:1 cylinder head. A Sprint intake and exhaust complete the package. Finding the correct carb can be a “challenge”. It seems that most of them have disappeared, with the exception of a few expensive NOS pieces. A standard Pontiac (fuel inlet on the front, not side like Chevy) Q-jet can be modified to work with the OHC-6, I will be doing this soon, and will let you know the details.
If you plan on converting to a manual transmission, the four-speed, the z-bar and the transmission are different then the V-8 version. The z-bar is longer to accommodate the difference in engine width, and the transmission uses a 3.10:1 first gear. This is very important in getting good performance from a standing start with a Sprint. The automatic that is used with the OHC-6 is a Super Turbine 300, which is closer in relation to a THM350 then a PowerGlide (from what I have been told). There are two versions of this transmission, an air-cooled used on the OHC-6, and a water-cooled used with the V-8’s. The transmission was also used in various Buicks and Oldsmobiles, and it is getting a little difficult to find anyone knowledgeable about these transmissions, or to get parts.
There are a few companies that offer speed parts for the OHC-6. The most notable is Clifford that produces camshafts, headers, and Weber carb kits. Although the engine will rev to 6500-7000 RPM, the usable power of the stock setup is closer to 3000-4500 RPM, as it runs out of breath any higher (although neat noises will happen !!!).
I hope this information has been helpful. I don’t want to get a reputation for ranting (although this one is a little better organized!), but a healthy OHC-6 is a beautiful thing. The folks on this list will have tons of information about this engine, as well as anything else you will need for your car.
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Content last modified: January 16, 2014 at 3:09 pm
Q: More OHC6 Rebuild Questions
OK, I think I have an idea of what to check, but still have some questions:
1.) The valve height should be from the top of the head to the tip? I would think that this is done without the valve springs. Is that the best way to measure?
2.) What is the oil restrictor? Where is it located? How can you tell if it is bad? I lost two camshafts (worn lobes) due to low oil pressure, so I want to make sure that my 230 HP Sprint cam will survive.
3.) Where is the 30 vs. 45 mentioned earlier? Valve angle doesn’t sound right, since they are perpendicular to the head. I have one ’66 head, two ’67’s, and one ’68; are they all the same in terms of performance and oil flow? Numbers don’t matter much, since very few people even know what the numbers are to be.
4.) What type of work do the cam followers require?
5.) What type of prep work should be done to the lifters? I know they can be disassembled and cleaned, and was planning on doing that, but is there an easy way to check the leak-down rate?
6.) Are rings and pistons still available? I know that one of the three engines that I have needs new rings. I was going to use the best parts of the three to make this new engine. What is a safe overbore? Does this cause any overheating problems like the V8’s?
7.) I am converting from an automatic to a four-speed. I have found the correct transmission (3.11:1 first) and all of the clutch parts. Someone asked about the Z-bar being a different length, that is correct, to compensate for the different width of the engine. Will the driveshaft have to be shortened? The manual for 1967 shows that they have the same “stripe”, so I would think they are the same. How about the yoke. Is there anything I have to worry about here? The transmission I have doesn’t have the yoke, so any ideas on where to find one?
A: Okay, I’m now back to the top of your letter after answering all your questions, and one theme runs through all those answers: INFORMATION!! Our experiences are always mixed with good documentation from Service Manuals and other forms of the printed word and number! We would not likely have learned so much without finding way more info than we could just looking at parts, so EQUIP yourselvles with a small personal LIBRARY regarding your car and automotive knowledge in general!
Albert Einstein said something like “Why bother remembering that which you can alway look up?”
1) Yes, from the top machined surface that the cam cover gasket sits on to the tip of the valve, but WITH the valve springs installed at the completion of the valve job. This info MUST go to the machinist who does this work!! If he is not willing to listen to your input regarding this stuff due to pride (“I’m not having some stupid customer tell me how to do MY job!”), FIND ANOTHER MACHINIST!
2) This is where the 1967 Service Manual becomes valuable! It describes, in words and pictures, how this system works. There’s a passage through the head with the restrictor, it’s between cylinders 2 and 3, and it is a piece of tubing about 2 inches long with an hourglass-shaped crimp in the middle of it that is about 1/8″ internal diameter. It then has an .080″ hole drilled in the side of the crimp, and the sizing of both the drilled hole and the hourglass crimp are critical to the flow volume and the pressure of the oil being fed to both the camshaft AND to the lash adjusters (lifters). Sometimes when poking around the holes and passages of a head being cleaned, these are damaged. They are also a bit fragile to try to remove from a head that hasn’t been hot-tanked enough to let it come loose.
3) Numbers MATTER ABSOLUTELY! The cylinder head numbers (to I.D. heads) are listed in Pete McCarthy’s first book, written for drag racers around 1981, including the NHRA minumum cc’s for racing, gives a good idea of which heads are which for mix-n-match engine building! I’m sure they’re in the parts books as well, send me your numbers, I’ll help you choose a head. The 30 degrees and 45 degrees refers to the valve face and the valve seat; when the machinist actually grinds on your head and valves, he’s cutting a surface that is angled. The only heads that are 45 degrees are the second design for 1969. All previous heads used the 30 degree valves. If there’s any doubt, give me your head casting dates as well. PS Ever heard of a 3-angle or 5-angle valve job? That helps shape the valve seat area for a smoother flow from the port through the valve. You cannot see the angle with head assembled, the valve need to be removed!
4) The current replacement followers have a rough and uneven surface that rides against the camshaft, and need to be machined smooth. I did mine on a veryfine knife sharpening stone, one-by-one, by hand. That takes a lot of cutting oil and from 1/2 hour to 45 minutes per follower. Jerry Woodlad describes this in more detail in his literature.
5) I use new lifters, they are a slightly different design, meaning they don’t have that little pin in the top hole, and you can’t mix-n-match with these.
6) Pistons for a 230 I believe are still available, but for 250’s have been difficult to find for some time. Safe overbore depends on the casting quality of your block, this applies to ANY engine! Usually try to stay at .030″, if you can find them, you might be able to do .040″, and I have done .060″. The rings are standard sixes to the industry, even the 6-cylinder Chevy used the same ring size, and even the same rod and main bearings! In my 250 inch engines I have also used modified pistons from a 307 Chevy V8, and there’s a piston in the 4.0Liter modern Jeep engine that may be usable. Its standard size is .005″ larger than our stock piston, 3.88″ instead of 3.875″. I haven’t got one in my hands for comparison yet.
7) Your driveshaft and crossmember should be the same. The only different crossmember was for the THM400, all others used one member, that covers all 3 years, 67-69.
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Content last modified: January 16, 2014 at 3:10 pm
Q: Engine Compartment Detailing
I am detailing my engine compartment and am wondering what were the original colors.
A: – What color is the transmission dip-stick handle?
….The Handle should be painted Engine Color.
– I have stock exhaust manifolds and a heat shield. The shield appears to have been painted black. Is this original or should it be left its natural silver color?
….I’ve seen restored cars with this part painted Black and I’ve seen unrestored cars with it left natural (Silver Zinc Finish). Also, early magazine road test photos show it to be Black. I’ll do some more digging thru photos and get back to you.
– Is the fuel line supposed to be painted like the motor? If so, how far up?
….Fuel Pump and Line would have been installed after Engine Assy was painted.
A: Dip stick tube should be natural heat shield should be black leave the fuel line natural filler cap should be painted if valve covers are Fan should be aluminum in color Cast aluminum brackets should be left natural. I have mine polished it looks pretty sharp.
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Content last modified: January 16, 2014 at 3:45 pm
Q: Heater Hose Bracket Color
My 1968 350 2-BBL was missing the bracket which attaches to the front of the engine and helps keep the heater hose away from the exhaust manifold (NOT the bracket which sits on the right fender well). I purchased a new bracket from Ames Performance. The part came in the same satin black color as many other parts in the engine compartment are colored. I can’t recall, is this bracket supposed to be the same color as the engine or should I leave it black?
A: Sounds like the bracket that bolts the pass. side head with the tang. This bracket is black and if seen it mounted in different hole(s) with the tang in different places. Think the far outside hole under the freeze plug is correct with the tang in the hole directly under it. In lower left corner of the head.
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Content last modified: January 16, 2014 at 3:50 pm
Q: Engine Painting
I have a 1968 Pontiac 350 engine that needs repainting. How was this engine originally painted. Was all of the engine painted Pontiac Blue or just certain parts and were there any other colors involved. Any info appreciated.
A: The block, heads, balancer, water pump, timing cover, intake manifold, oil filter bracket, and tin (except chrome of course) are painted blue. Black goes on pulleys, power steering pump, accessory brackets, motor mounts, heater hose bracket and coil mount bracket. Hope I did’nt forget anything.
A: When using this engine paint be SURE you use engine temperature primer first. It is made for very high temperatures. If you don’t use it first you can be sure your engine paint will peel off in sheets after you’ve run the engine a while. Any automotive store that sells the correct PMD engine paint should carry the primer too.
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Content last modified: January 16, 2014 at 3:51 pm
Q: Repaint Engine Block
I want to repaint my engine block but it appears greenish blue. I thought it was suppose to be Pontiac Blue.
A: The greenish blue is the color the original blue metallic goes after the motor has been hot and cold for 30 years. I have seen people attempt to reproduce this “aged” color, but I think that if you want to paint the motor – do it as advised on this list – the bright metallic blue looks sensational – people who are ignorant think that its not original its such a pretty color.
A: I was reading through some of my old Firebird-L emails, and ran across the thread about engine colors. This reminded me about a conversation I had with an original owner with a 1967 326 Convertible this past summer. He had restored his car a few years ago, and it is now an AACA senior car.
Anyway, the engine is painted Buick Green. I asked him about this, since it was a very nicely restored car. He said that he gets in trouble for that all the time at shows. The story is that early in the production of 326 engines, there was a fire at a plant somewhere in the supply chain. Pontiac Blue (Plasticote #227, that we are all familiar with by now) was not available, so they painted the engines in a metallic green that was for Buicks. I don’t know the dates, but maybe some people with original cars could try and determine a range. His car was purchased in March of 1967, so it probably occurred in cars that were built in February.
I would guess that this only applies to 326 engines, as the OHC6 and 400 were probably built in different plants/assembly lines. Does anybody know where these engines were built?
Just adding a little fuel to the fire, and maybe helping those that thought their engines were green gain some sanity.
A: I was able to buy the correct 1969 Pontiac Engine paint at Parts America, which is now Advance Auto Parts. The brand they carry is Plasticote and it is called Pontiac Blue Metallic. This is the same paint that Performance Years sells and may be the same as the others too, I don’t know. When you paint with it, it will look just like the factory brochures show the engines. However, as noted in the Ames catalog, after exposure to heat it begins to pickup a green hue, as the original factory paint did.
A: PEP Boys in California has a high temperature primer. Plasti-kote engine enamel, good to 500 degrees F. I have found Plasti-kote to be very good paint. Probably as good as Krylon. That is a big deal for me because Krylon harbors so many good characteristics, not the least of which is fast dry time and recoat any time. I think the number is #8334 for gray, but might be a lot number. They make the good Pontiac (metallic) blue/green engine paint, #228?
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Content last modified: January 16, 2014 at 3:56 pm
Q: Pontiac Engine Paint in Brush Form
I should be repainting my 1968 Firebird’s 400 in the next two weeks. I was wondering if you folks know of any place (chain or mail order) that sells the Pontiac Blue paint. The catch is that I don’t want spray paint. I plan on using a brush, as sprays don’t seem to get into cracks well. I haven’t asked at any of the local stores, but I only remember seeing bright spray paint colors.
A: POR 15 by restomotive laboratories should have the brush on type. I bought some years ago and it has more shine to it that standard engine paint. Also, you could try Bill Hirsch. Both are reputable. Look them up on the net, or in Hemmings.
A: I too have used the POR-15 engine paint. My experiences were that it does seem to have a higher gloss than some others. It goes on rather thick (outside temps were in the 80s when applied), and would show the brush marks on any very flat surface such as the oilpan, valve covers, or valley pan. On rough surfaces such as the engine block or heads, the brush marks cannot be seen.
The sales person indicated that it was more heat resistant than other paints, but I managed to burn the paint off the exhaust ports during the cam break-in period. My carb was running lean at the time, so that added to the heat output.
If the block isn’t cleaned of dirt and grease and hasn’t been scuffed, don’t expect paint to flow and adhere properly. It’s sometimes a little like welding or soldering. The work must be free of contaminants for the best results. Those brush marks will only get more noticable with age, as the paint solvents out-gas and the paint tightens and shrinks slightly.
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Content last modified: January 16, 2014 at 3:58 pm
Q: Correct Engine Paint for a Fanatic
I have tried several different engine paints but none look correct or last for more than a year. Has anyone had success with any engine paint?
A: Well after much searching, I found an engine restoration Co. on the East Coast Bill Hirsch Automotive that specializes in these products. They have it in pints or aerosol cans.
They have tons of other restoration products, but I was hot to get the correct engine paint, so I just got that and some 1,800 degree exhaust paint for the headers.
So I answered my own question! But here is the link just in case anyone else is looking for this type of product in the future or for reference in the Q & A section! This is just one place to find it, I’m sure there are more, but I jumped at the first one!
http://www.hirschauto.com/
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Content last modified: January 16, 2014 at 3:59 pm
Q: Ram Air Info Sheets for 1968
I found a document in the glove compartment of the 1968 RA II ‘Bird I recently purchased. One shows upper pan installation and second the lower pan. The detective work done by Generation-1 Registry about mods to hood ARE RIGHT ON AND DOCUMENTED HERE!….amazing piece of pontiac hi-performance history thats for sure… this is fantastic!! ive NEVER seen anything like it, have you ??
A: Thanks for the information and what a find!! Lots of gems out there waiting to be found.
1968 Ram Air Information Sheet One
1968 Ram Air Information Sheet Two
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Content last modified: January 16, 2014 at 4:21 pm
Q: Ram Air Kit for 1967-1968
Where can I found a Ram Air kit to put in my 1968 Firebird 400.
A: There is no kit that I’m aware of for the 1967-1968 Firebird Ram Air System. A kit would consist of the Upper Hood Baffle, Lower Carb Shroud, Hood Seal, Shroud Seal, Air Cleaner Lid and open scoops.
A few years ago, Barry Martin (Sonic Motors) had the Hood Baffle reproduced. He only had around 5075 pieces stamped out (kirksite die) and vendors were selling these for $350-$425 ea. Not sure if any are still out there. The Carb Shroud is the same as 1968 GTO. Used ones go for $500 or so. I understand that someone has or is doing a Carb shroud. Figure this to be in the area of $300 or more. The foam seals are available thru most repro companies. The Carb lid is also available repro. Scoops would have to be cut out; repro’s are available. If you bought all the pieces used or repro, figure around $1500 for such a ‘kit’.
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Content last modified: January 16, 2014 at 4:24 pm
Q: Identifying a Ram Air
Hello Everyone! I am new to the list. I am trying to restore a 1968 Firebird just for run, and I was wondering how do I know if it is Ram Air I, II or neither? What exactly is Ram Air?
A: The engine block would have codes:
WI – Firebird 400 Ram Air I (Manual)
XN – Firebird 400 Ram Air I (Auto)
WU – Firebird 400 Ram Air II (Manual)
XT – Firebird 400 Ram Air II (Auto)
More information at: https://FirstGenFirebird.org/1968-info/1968-technical-information/68_id_numbers/
Also look for the Ram System: Upper Hood Baffle, Lower Carb Shroud, Hood Seal, Shroud Seal, Air Cleaner Lid and open scoops.
More information at: https://FirstGenFirebird.org/f-a-q/category/ram-air-specific/
A: Ram Air is an additional performance option on Sport Option 400 Firebirds. It has an induction system that has open scoops on a 400 hood, a big pan bolted to the underside of the hood, and an air cleaner that has a raised rubber ring to seal the housing to the pan. The engine has some internal differences, and RA I is different than RA II in such areas as heads, exhaust manifolds, cam, etc.
You need to check the numbers: 2 letter engine code (on block under right head), 9 digit partial VIN (right side of block next to timing cover, just above oil pan) and heads (large numbers on center exhaust port boss), plus date codes of block, heads, manifolds, firewall data plate. You may also want to look for codes on the transmission and rear axle. You can find a couple books that have these codes, and most are pretty accurate, but not perfect. Isn’t that info somewhere here on Geoff’s site? Report back to the list, we’ll help you decode. Date codes are cast onto the part, are a letter followed by 3 digits. Firewall data plate code is different, it’s 2 digits followed by a number.
You may also want to get the Pontiac Historical Services package on your car to see how the factory built and equipped it http://www.phs-online.com I believe the cost is $35.00. Chances are very good that your car is not exactly the same as it was 32 years ago, so this will tell you what your car was when new. Information is the key to knowledge!
Many Firebirds have 400 hoods and engines added, this does not make it a Firebird 400, it becomes a modified 6 cylinder or 350 car to most judges and prospective purchasers. The fact that we can document our cars is part of the fun of owning Pontiacs over all other brands of American 60’s and 70’s special interest automobiles.
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Content last modified: January 16, 2014 at 4:26 pm
Q: Ram Air Differneces Between the Years
I was thinking about reproducing the Ram Air equipment. What are the differences for the different years.
A: ….The Ram Air Hood Baffle will physically fit all 1967-1969 Firebird 400 Hoods.
The Ram Air Carburetor Shroud will physically work on all 1967-1969 Firebird 400s and 1968-1970 GTOs. There were apparently (2) types of Shrouds; (1) with the provision for the Heat Riser and (1) without. Those with are not very common. As for the Hood Baffle, some say that 1967 Firebirds had a ‘tab’ on the bottom of it (to hold the Seal ?)
Though, I’ve never seen this on any original 1968 Ram Air Firebirds. I’d say with such a large range of applications, both the Hood Baffle and Carb. Shroud would be excellent candidates for reproducing provided the retail price wasn’t too high. Many would ‘add’ Ram Air to a “400” Hood if they could get the Hood Baffle and Carb. Shroud for a reasonable amount. Of course, being able to sell them cheap depends on quantity. If you have connections into the Die-Making World, you could have tooling made for not too much. If you’re a full time, major restoration parts business, you’re likely going to mark these up quite a bit to make a nice profit.
A: As for the “tab” on the upper hood pan, the orginal 1968 I had that I sent you a pic of had one. Also the setup that was sold on e bay was a 1968 and had the same. I made an impression of the tab before I sold mine a few months ago.
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Content last modified: January 16, 2014 at 4:27 pm
Q: Ram Air Shroud from 1968 fit a 1967
Will a Ram Air Shroud (air cleaner) from a 1968 Firebird would fit a 1967?
A: All 1967-1968 Firebird and 1968 GTOs that came with Ram Air used the same Carb. Shroud (Air Cleaner Housing) and Lid. There were no Carter carbs. used on any 1967 400 Firebirds. The RA Hood Baffle was also the same 1967/1968 Firebird but different on the 1968 GTO (though, they initially look the same).
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Content last modified: January 16, 2014 at 4:28 pm
Q: Rain and the Ram Air Scoops
All this talk about ram air hoods got me thinking and since i’ve never had the pleasure of viewing a real ram air in the flesh I ask. What do you do when it rains? How do you keep the water out. I can’t imagine people in the sixties buying cars you drive in the rain.
A: To answer this we must rewind to 1965 and look at the GTO. It had an over the counter option of a Ram Air pan that bolted on to the 3x2s (triPower). It had a seal that moulded itself to the contour of the underside of the hood. It didnt have a seperate hood pan as in the later years. In 66 Pontiac continued this over the counter option and later that year had a factory option of RA GTO. This was the first time you could get a purpose built factory Ram Air Pontiac. There were previous cars built in the early 60s but werent avaliable to the general public. There were around 200 of the 66 GTO RA cars made. Rare indeed.
The tradition of RA carried into the 1967 GTO but tripower was replace by single 4 bbl(Q-Jet). When Firebird was intoduced the 400 option had a newly designed scooped hood that also offered the RA setup except it had a seperate under hood pan to help seal and direct the incoming “rammed” air. These were true Factory Hot Rods avaliable to the general public.
Tradition carried on to the 1968 GTO and Bird with basicly the same setup. This was the first year GTO used a seperate hood pan. Complaints of this fair weather only system promted enginners to design a 1969 driver controlled system that closed the RA inlets off to under hood inlets. This allowed the driver to choose if weather was not favorable. 70 Trans Ams improved the design and had a flapper that faced backwards on the shaker scoop. This was carried on thru the 72 model. After that it was basicly a design feature. It was big hoopla that GM introduced the Trans AM with factory RA in the last 3 yrs. History does repeat itself.
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Content last modified: January 16, 2014 at 4:29 pm
Q: Ram Air V
I have heard Pontiac made some Ram Air V in 1969 but were available in a crate only. If they were crate motors could you not have put it into a Firebird?
A: … the factory didnt put these race motors in any production cars. A little over 200 were sold in the crate and some more were pieced togeather. There was 2 versions. the low deck 303 cu in version made just for Trans Am racing ( 5 litre restriction),and the 400 version . The factory tried a few experimental versions,366 and 455 but the RAV program was aimed at the drags and T/A series. They also experimented with various carb(s) and manifolds. the closest production motor to this was the 73-4 455 SD.
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Content last modified: January 16, 2014 at 4:31 pm
Q: Sprint Option
I currently own: 1968 Firebird, Straight 6, 4.1 Litre overhead cam, 2-speed powerglide with 72,000 miles – unrebuilt.
I have heard the following things:
1) a 4.1 litre was more rare than the common 3.8 litre overhead cam – Question: Is this true?
2) that the basic configuration that my car currently has is almost impossible to find nowadays. – Question: Is this also true?
I am trying to figure out what my car is actually worth, but I do not know enough about the cars to figure it out. I am also trying to figure out if my model of car is actually as rare as people say it is. Everything on the car is original – it still has the original floormats. It is about 15% off of “mint” condition (does that statement make sense)? It burns a trace amount of oil – I believe it needs a ring job / rebuild I would like to know if dual exhaust came with the standard 2 barrel 326 convertible, or if this was an option that had to be ordered.
A: 1) Yes, the ‘Sprint’ option is hard to find and it is worth more. Also harder to find parts. The most popular Firebirds are the 400s and Ram Airs. I consider the Sprint to be in the same class as Ram Airs, cherished rare cars. I have yet to see both of them in person.
2) Same as above, only 7459 Sprint cars (including Tempest) were built. According to a couple of sources, the Sprint came standard with OHC 6, 4 bbl, at 215 hp at 5200 rpm. There were 1850 Sprint equiped powerglide cars.
3) It is desirable to have all the original equipment and accessories and new “mint” condition. I wish my car did so I did not have to scavenger around for parts. I still can not find some accessories. From the above information, I would be surprised if you could not get over $10,000 for it, more if it is a convertible. I have a hard time putting a definitive value since I can not see the car, market differences, and if you can find someone willing to pay top dollar.
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Content last modified: January 16, 2014 at 4:39 pm
Q: Differnece between Sprint and Regular OHC-6
What was the difference betwen a regular OHC-6 and the Sprint. I know the Sprint came with a 4BBL and a hotter cam
A: The Sprint package included these items you mentioned, also a higher compression head, larger balancer,low restriction exhaust with split exhaust manifold, dual valve springs, different distributor,different engine bearings and a few other things. You can add any of these items to fit your budget. I do have a complete running(still in the car) 1967 Sprint motor with new cam and followers for sale. email if interested.
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Content last modified: January 16, 2014 at 4:41 pm
Q: Sprint Build-Up
I want to make a Sprint out of my OHC-6. I realize this decision also involves a number of different changes – interior as well as exterior.
Anyone have the list of options the Sprint came with? I know a 3speed was standard, but was there and automatic? From the Master List from Pontic Historical it seems only the 400 got the Hydromatic, everything else got the 2-speed automatic, but did Sprints come with them? I’d think surely so, but you don’t know til you ask.
So far, this is what I’ve gathered that needs to be changed\added:
From Standard to Custom interior
Sprint Hood Emblems
Rocker Panel Sprint emblem
Sprint cam
Things I have no way of knowing: Other engine and engine compartment changes – oil pump, water pump, alternator, battery, etc.
A: in fact you could get a Sprint with the 2-speed automatic, even mounted on the column! The Sprint option on the ‘bird was basically the engine, so if you’re going to add options, why not just create the car the way you want? Maybe stick with the neat triple teal color scheme plus the Sprint engine, plus whatever trans you’d like. A 4-speed with a tilt, hood tachometer and gauges, and a modern stereo. Some suspension mods, just enough for it to handle better, and a single piston front disc brake system from a 1969 bird or 1969-72 A-body.
A: There were TWO Sprint camshafts, the “E” cam and the “H” cam. The great unknown right now is whether you have a Sprint cylinder head, and you won’t know it until the cam cover comes off. The casting and date numbers are inside. The cam is marked on the end like a V8 cam. “A”, “B”, “C” and “D” cams are from one-barrel base engines. The “E” grind is what Jerry Woodland made a run of several years ago, but I don’t think he has any left. Gary had a local machine shop make an “H” pattern some time back to do regrinds, but you’ll have to discuss that with him. The “H” Sprint cam was used ONLY on 1969 manual trans cars, while the “E” cam was used on all 66-68 Sprints, and the 1969 THM350 Sprints (they quit the 2-speed option for Sprints only in 69).
There were no obvious changes under the hood except the engine – higher compression head, the 4-barrel and the dual-outlet exhaust that went to a Y-pipe. Outside the only difference was the rocker emblems, as all the OHC6 Firebirds had the “4.1 Litre OVERHEAD CAM” emblems. The manual trans cars came with the 3.55 ratio axle only. The automatics in 68 came with 3.23 as Standard release, and the 2.78 Economy or 3.55 Performance release axle ratios as options.
While the Custom interior is nice (and a favorite of mine, especially the Teal), it is a separate option from the Sprint package. Also separate were the posi rear, console w/floorshift on automatics, and anything else you might think was a performance option. The standard trans for the Sprint option DID come only in the Hurst floorshift however. One-barrel manuals were supposed to be on the column, but I have never seen a manual column shift in a 1967, 1968, and 1969 ‘bird.
A: The stripes were just like the HO stripe, but with no lettereing on the Firebird, and WITH the word “SPRINT” on the A-body cars. My Dad’s 69 LeMans Sprint convertible had them. They were available on Tempest/LeMans cars for all 4 years 66-69. The Firebird’s plain stripe was actually available on any 1967 and 1968, but the H.O. came standard with the lettered version. There were no stripes in 1969 on the Firebird until the Trans Am.
A: You mention the one that I didnt… the rocker panel emblems. However the hood emblems are the same as base OHC-6. Have fun adding whatever you want to the car…. if done properly and tastefully it will add to the value of the car. I would also (space permitting) save any orginal parts you have from the change over. I disagree that the Sprint option was an engine option. It was aimed at being a total package of ride and handling and performance. The idea of this was the first T/A type “tuner”that Herb Adams built, called PFST(short for PontiacFirebird SprintTurismo).It was based on a 1967 Sprint hardtop with triple webers, shaker scoop thru the hood, very large tire and wheel combo,upgraded suspension and brakes. This 300 hp Sprint would handle better than the V-8 counterparts and eat their lunch on all but the longest straightaways. Its too bad that tire melting muscle cars pushed the better balanced Sprints into extinction.
A: Sprints came with heavier springs,shocks,4 bbl with dual valve springs, different duration and lift on cam(same diameter valves)larger harmonic balancer, smaller chambered head to raise compression,split exhaust manifold with y pipe,larger clutch & Hurst floor shifter(manual trans). Different fuel pump,distributor,rear end ratio,larger tail pipe,and engine bearings. Im sure Ive left out something…
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Content last modified: January 16, 2014 at 4:41 pm
Q: Sprint Coil
Have a question about coils. Started having ignition problems on the 1968 droptop Sprint I’ve been restoring, so I went to replace the coil as well as condenser/rotor/etc. Went down to Napa and discovered the coil listed in all the catalogs is a typical oil-filled can style. What I have on my car (and judging by the rust and Delco Remey logo on it it’s original) is a much shorter air cooled coil. Looks more like something off a newer electronic ignition vehicle if it weren’t for the tower on top. Has a round coil in the middle, a square frame around the middle, and a bracket that bolts it to the block just aft of the distributor. Threw the Napa guy and all his contacts for a loop. I went ahead and bought an internal resistor coil and bracket and am looking for ideas on where to mount it, because it won’t fit where the original coil was. Questions:
1) Ever seen a replacement coil that matches the original?
2) If you converted at some point to a can style coil, where did you mount it? Firewall, fender, ???
A: The shorter air cooled coil is correct for the 1968-1969 OHC-6.
1966-1967 used a conventional oil filled coil. They had 2 different ignition systems for 66 and 1967 Sprints. The 66 used the infamous TI or Transistor Ignition. 1967 was improved (or so they say) to the newer CD or Capacitive Discharge ignition.
I have one of the TI ignitions for a 1966 Sprint and have been told there were only about 200 made. I also have most parts for the 1967 CD set up. Of course this wont help your situation but if its not a points judged car chances are 99.9% wont know the difference anyway. I say put a pointless conversion and conventional coil in and cruise on.
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Content last modified: January 16, 2014 at 4:42 pm
Reference:
- 1967 Dealer Technical Bulletin 67-T-13
- 1968 Pontiac Service Manual figure 6-18
- 1968 Dealer Service Information Bulletin 68-I-68A
Q: Heads for 350 2-bbl converted to 4-bbl
A: With regard to the original post about cam selection for a 350 2-bbl converted to 4-bbl, I would suggest the Pontiac 067 or Summit 204/214 cam which was offered by someone on the list. I would go NO HIGHER than the 204/214 for your application, since you specifically wanted low end torque and gas milage. In fact I think the Summit 204/214 is probably a great bet for your needs.
A: Well put. Pontiac engines like a wide lobe center, in the region of 110 to 114 degrees. This will give you better idle characteristics compared to a cam with simular lift and duration, but with a tighter lobe center.
In addition, the port design in Pontiac heads favor low lift figures, which is why you see the factory cams with lift figures of .406″ (the exceptions are the “44” cam with .410″ and “041′ with .518”). Adding more lift is waste of time since the port design doesn’t flow any better at higher lifts.
It is said that Malcolm McKellar, an engineer at Pontiac in the 50s and 60s believed that higher lifts reduced the reliability of the engines with higher stresses on the valve train. He felt that lower lifts, along with port designs that favored efficiency at low speeds woul still make good power, but not at the price of valve train failure.
That, and the restricive exhaust ports demanded a balance between the intake and exhaust side.
As Steve suggests, either go with a Pontiac high performance grind, or an aftermarket cam that is very close. And read the Jim Hand information. He is the guru of Pontiacs, and he’s done all of the testing and experimentation for us.
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Content last modified: January 15, 2014 at 12:18 am
Q: 350 2bbl Build-up
I am trying to figure out the best way to get performance out of my 350 2bbl.
1. Whant is the best Intake
2. what would ba a good carb.
3. What would e the Biggest cam I could use with a stock valve train
4. How much can I mill the heads
The reason for this is to keep the stock motor and for the Sleeper look with April gold paint and Ivy gold Interior!!
A: The 350 2 bbl buildup has been discussed at length both here and on www.classicalpontiac.com, I suggest getting a cold one and do some reading. Just go to www.classicalpontiac.com, click on QandA, then try BOTH archive #6 and the current QandA and search the title for “350”.
Also, I reccomend going to http://www.classicfirebird.com/hand/hand.html and reading the complete series of articles by Jim Hand.
The best “peformance” from you engine varies depending on your goals for the car, so it would be best to give more detail about what you want to do with it, from a quiet easy to drive and mild mannered street machine to a lumpy idle, no low end torque, race engine.
Also, I’m always an advocate of following this sequence when building up a car.
-
Decide on some general goals for the car. Why? Because your car will have the best “performance” when all components are matched up well and working in harmony.
-
Tune, Tune, Tune. Why? Because you’ll need to learn how to do that well anyway when you’ve built your “ultimate” engine, and you can often squeek a lot more performance out of your current engine, for almost no money.
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Start with everything EXCEPT the engine. Why? Because to make the most of your car you will need to do this anyway, and sometimes this may be all you want/need. Start with rear end gears (remember, matched to your goals), tires, and transmission/torque converter.
-
Now do your engine stuff…….
Finally, here is the very, very short version of answers to your questions…assuming a “normal” streetable car.
* 1967-72 Intake
* Quadrajet
* Duration wise no physical limitation. Lift around .450 General consensus is no more duration than 214/224 at .050 but I have no personal experience with cams this big in a 350, and some people run bigger ones and are happy.
* If virgin, .060 is all you can go. This will take 12 cc from the chambers.
There are caveats to almost all of these answers. Again, a good search of the QandA on classicalpontiac.com will expose all of the details.
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Content last modified: January 15, 2014 at 12:19 am
Q: “Numbers Matching”
How do you know if you have a numbers matching car.
A: People still call cars “numbers matching” if all of the Part Numbers and Casting Codes are correct and pre-date the car by the correct 1-3 months (in general).
A:
Use the following web pages on the First Generation Firebird web site as a guide:
1967: https://FirstGenFirebird.org/1967-info/1967-technical-information/1967-drivetrain-id-number-information/
1968: https://FirstGenFirebird.org/1968-info/1968-technical-information/1968-drivetrain-id-number-information/
1969: https://FirstGenFirebird.org/1969-info/1969-technical-information/1969-drivetrain-id-number-information/
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Content last modified: January 15, 2014 at 12:21 am
Q: Changing to a 4 Barrel Carb for a 1968
When changing from a stock 2 barrel setup, to a 4 barrel, what parts are need to be changed, and what donor years are ok. The car is a 1968 350 automatic, and I have a freshly rebuilt Q jet.
A: It’s not a difficult swap, but there are a few gotchyas to look out for.
-Spreadbore intake castings are pretty much the same from 1968 thru 1972. In 1973, Pontiac started using an EGR valve, and in 1976 or 1977, the intake was redesigned with more restritive ports. Thes are identified with an odd waffle imprint on the rear of the intake, behind the carb flange. These characteristics make these later intakes less desireable. Some 4bbl. intakes before 1968 were for squarebore carbs (using Carter AFB carbs), and the 1967 Qjet intake has an odd heat passage on the carb flange.
-Throttle cables and cable brackets differ from 2 bbl. and 4 bbl. applications. You will find that your 2 bbl. cable will not give you a full range of motion and may require some fabrication to get full throttle. Reproduction 4 bbl. cables are now available from Performance Years. You’ll have to hunt the scrap yards for the bracket, or modify yours. (Need link to modify instructions)
-More on throttle brackets. Pontiac used a rod for 1967 cars, and then went to a cable for the 1968 and later cars. This cable is very different from that used in later Chevy applications. Around 1970 or 1971, the cable and bracket design changed again, eventually evolving to be more like the Chevy design. So, beware of cables or brackets from earlier or later cars (you don’t indicate what year your car is).
-You’ll need a 4bbl. aircleaner. If you insist on a stock look, try First Generation Firebird’s, ebay’s, Classical Pontiac’s classified pages.
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Content last modified: January 15, 2014 at 1:10 pm
Q: Models of Rochester Quadrajet Carbs for 1967
I was wondering if my car should have a Q-jet or not. I have a 1967 Firebird 400 convertible I’m trying to get back to original condition. Does anyone know what carb and number was stock?
A: Here are the five different models of Rochester Quadrajet carbs used on 1967 Firebirds with a 400 cid engine:
7027272 .................. 400 cu.in. A.T. 7027273 .................. 400 cu.in. M.T. 7037272 ........ 400 cu.in. A.T. w-A.I.R. 7037273 ........ 400 cu.in. M.T. Ram-Air* 7037276 ........ 400 cu.in. A.T. Ram-Air* * With or Without A.I.R
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Content last modified: January 15, 2014 at 1:12 pm
Q: Rochester 4bbl Carburator for 1968
I have a chance to buy a Rochester 4bbl carburator for my 1968 H.O. How much is this worth since it is already up to $200 on eBay?
A: The 7028269 Rochester 4Bbl Carb was originally used on all 1968 Tempest and Firebird 350, Manual Trans, 4Bbl engines.
According to the PMD Engine Production Log Records:
2,658 “WR” code (Tempest) 350 HO 4Bbl, M.T. engines were built. 3,784 “WK” code (Firebird) 350 HO 4Bbl, M.T. engines were built.
So, there were 6,442 engines built that year using the # 7028269 Carb. Additionally, there were Service Replacement Carbs. mfg. with this same number. (though sometimes found with date codes 1-3yrs. past production.) Not sure where the seller came up with the production number of 1,400 and that all carbs were built on the same day. I’d have to see documented evidence before believing that one. Carbs. were generally built to spec. according to build orders unless the carb was some odd-ball, low production unit such as RAV.
Speaking of Date Codes, some early production 1968 model Rochester Carbs did not have a date code. Others were stamped on the LH, Rear edge of the Throttle Body (lower section). Most date codes were stamped on the Bowl Assy. near the Rochester Assy Number. Date Codes used the Julian Date System. (day of year- 3 digits followed by last digit of year)… 245 8 (245th day of 1968, ’78).
If your Firebird is documented as a 350 HO car and you would like to have all the numbers match, you might want to pick this carb up. I wouldn’t get too carried away in the bidding war… this is not a “rare” carb. Considering a good rebuild can cost upwards of $300+, I wouldn’t spend over $200 on the carb as it is. Of course, if you’re a numbers nut like me, money sometimes isn’t the primary issue.
Best advice: wait and bid just before the end of the auction.
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Content last modified: January 15, 2014 at 1:13 pm
Q: Quadrajet Carb Problem
I have a 1968 Firebird 400 with a Quadrajet carb. The engine is idling to high (1000 RPM or so in drive) when warm with the choke open. The idle adjust screw is backed all the way out and the mixture screws are adjusted. No detectable vacuum leaks and the throttle linkage is loose at idle. The only modification is an open element air cleaner.
Any ideas as to why the car is idling high? If you think I need a rebuild, any suggestions for my daily driver?
A: Check the SECONDARIES …. these are always overlooked … and should be closed under an idle condition. If this isnt it then check the set screw that adjusts the butterflies.
A: I’d bet the problem lies in the orientation of your throttle linkage, throttle cable, or throttle cable bracket. Pull the keeper pin that holds the cable to the throttle linkage. Let the linkage relax to the closed position. Pull the cable all the way out with your fingers and hold it next to the point where it hooks to the linkage. My guess is that you will need to shift things around a bit to get the eye hole in the end of the cable to reach the throttle linkage connection point in its closed position.
A: I just hadthe same problem with mine .. I ended up looking at the petal itself , over the years it has been hit so many times that it was bent …{ my lead foot }… so it stayed about 1200 rpm … I had to rebend the petal to set it right
A: Did the problem happen all at once?If so is the choke step coming off all the way?This type of setup likes to bind.A little wd 40 or liquid wrench will solve the problem.My Bird stays parked alot so the linkage will bind and a quick shot with the spray and away I go
A: I’ve had that happen and the secondaries staying open were the problem as pointed out earlier. Another guess….Could it also be that the float needle is not seating, or might be worn out???
Is it possible that you did something out of the ordinary that might have caused the problem? Perhaps dropped a tool on the carb while working on your car and bent some carb linkage?
Another thought…. Is there a slow idle solenoid on the carb? Is it stuck?
My last shot at it…. You may have gotten to close to a Rice Burner and sucked it into the carb. No big deal. Just push it all the way in.. Your bird loves seed!
A: It’s either a vacuum leak or ignition timing. check your timing and make sure it’s at it’s proper setting. To check for vacuum leaks, unplug one vacuum line (from the carb) at a time and plug the port. If the idle is unchanged reattach the line and move to the next line. After you’ve verified that the lines and their accessories are working properly, take some WD-40 and spray it on the throttle shaft on the bottom plate of the carb. Next move to the carb gasket and spray all around it. Lastly, spray the intake manifold around the intake ports at the heads.
A: i would bet the front butterflies are not closing properly if so you might have some build up in the bores of your carb. look into the bores with a flashlight and see if you see any build up that sort of looks like water scale where the butterflies touch the bores when closed i hade this problem before you might can clean it but would be better with a rebuild
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Content last modified: January 15, 2014 at 1:15 pm
Q: Gasket between Qjet and intake
While spraying Gummout carb cleaner down the primaries on my Quadrajet carb on my 1968 400, I noticed that the Gummout was leaking out from between the Qjet and the intake. Not a good sign. I assume that is my problem (or I created the problem with too much Gummout carb cleaner).
Here are my questions: Should I use gasket sealer on the new gasket or should it go on without and sealer? Do I need a torque wrench for the bolts?
A: This may or may not be a fix, but ………when I got mine OHC running it was missing out a little. Then it was suggested that there was a thin metal gasket that should go between the bottom of the carb and the intake. I went to a speed shop and got a thin gasket ( it was just a thin piece of sheet metal with the 4 holes in it ) and voila, I have not had any problems since. Apparently it always had one on it and when I took the car apart I either lost it or chunked it. I think it cost about $5 and was in stock hanging on the wall at a performance shop. May be worth a shot.
A: This same gasket is needed on 1967 Qjet intakes as well. There’s a heat passage along the intake in front of where the carb sits. I know, I learned this one the hard way!
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Content last modified: January 15, 2014 at 1:17 pm
Q: Carter Carburetor Adjustments
The carter carb is very similiar if not almost identical to an edelbrock 600 cfm carb. I really need assistance and desperately. One of the questions is about the two screws on the front of the carb at the base. What should these screws be turned to? The carb has an electric choke and how should this be set? And would there be any other adjustments that I could do to it? I seem to be getting much poorer fuel mileage that the stock carter carb that was on the 326. I bought this new carb thinking I would increase mileage but has turned just the opposite!! This could be because I do not have it adjusted right. I really would appreciate any help that someone can give. Thanks.
A: The two screws on the front are the idle mixture screws turning them out (counter-clockwise) will richen the mixture & vice versa.They have no effect on the mixture at cruise(in otherwards if its too rich at driving speeds adjusting these will not help) as for setting them,the only real “correct way” is with an exhaust gas analyzer.Setting with a vacuum guage may work but likely the smoothest idle will be too rich if your state does emission testing.Having said that try turning the screws in one at a time (with the engine off) & counting the number of turns on each(In a perfect world they should be the same) then back them both out to the smaller number of turns.Now restart the car (which should have been already warmed up).Now try turning both of the screws 1/2 a turn in,if the car starts running rougher you are too lean (& you should back the screws out again & try going out in 1/2 turn increments until you find it makes no further improvement then go back in 1/2 a turn or so),if the idle improves try another 1/2 turn until you find where it starts to run rough then back the screws out 1/2 turn or so.Basically you are trying for the smoothest idle & then (slightly) leaning the mixture.
As for the choke setting,basically you want the choke valve to just close on a long cool off (sitting overnight or a number of hours) this is assuming that the weather is mild (so when it is really cold it will be closed with more tension).The plate should be open completely after approx 5 minutes running time no more than 10 anyhow. I hope this helps..
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Content last modified: January 15, 2014 at 1:19 pm
Q: Adjusting Idle Fuel Mixture
The idle fuel mixture seems to be too rich. I have fiddled with the two idle screws on the bottom of the Q-Jet carb but it still runs too fat. Stinks up the neighborhood. Is there a systomatic way of trying to lean out the idle rather than me just turning screws.
A: The mixture screws are the only control for idle fuel mixture.The carb’s main jets control the mixture the rest off the time.The idle circuit is metered through the main jets,then through some calibrated restrictions which are difficult to modify. Changing the main jets will have no measurable effect on the idle mixture.I have found though,that sometimes people think the mixture is too rich when they smell unburned fuel coming out the exhaust and the problem is actually that it’s too lean causing poor idling/misfiring and the unburned fuel smell is from the misfiring.Obviously you want to check for vacuum leaks,timing,dwell (if you have points) etc.Lastly,a high mileage engine may emit a lot of unburned fuel from lack of cylinder sealing even though it seems to run well.Just some food for thought.
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Content last modified: January 15, 2014 at 1:21 pm
Q: Stock Carburetor Application for 1967
Can anyone tell me once and for all what carb came stock on a 67 firebird 400? I have a lot of conflicting information on weather a Rochester quadrajet or a Carter AFB.
A: For 1967 Firebirds…only the 326 H.O. used the Carter Carb. All other applications used the Rochester.
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Content last modified: January 15, 2014 at 1:22 pm
Q: Carburetor – Converting From 2 BBl to 4BBL
I’m converting my 1968 2 BBL to a 4 BBL EDELBROCK Performer 600. I’m up to the point of making connections to the carb (linkage, fuel line, air cleaner, vacuum lines). I have the following questions (I know several of you have done this).
Note: Bare in mind that the article in the Jan.99 issue of Car Craft covers a 4bbl Qjet to 4bbl Edelbrock swap. The article is a little lean on details in any case.
1. The carb didn’t come with any linkage parts or documentation (I bought it used). The original accelerator cable doesn’t reach the throttle points on the carb using the stock bracket. Any suggestions on how to hook this up?
2. The fuel line originally bolts to the front of the stock carb. Now it “routes” to the right side of the carb. and requires an inline fuel filter. I bought a Specter glass filter. Are there any kits for hooking up to the stock line or do I need to make my own.
3. I also installed the Edelbrock Performer intake. What’s the best point for connecting the vacuum advanced and PVC valve (do I even need a PVC valve)? On the 2 BBL setup, there was vacuum point on the intake connected to a port below the throttle butterfly. Is it still needed?
4. The stock air cleaner had an air breather tube connector to the top of the right valve cover. Is this still needed, or can I cap it off.
5. What do I do with the large ports at the top of the Edelbrock carb. Do I cap them off?
A: Q1: You will need to get an aftermarket bracket. It will bring the cable closer to the throttle lever on your carb. The Edelbrock catalog shows a number of linkage accessories that might be helpful.
http://www.edelbrock.com/
You may need to fabricate something for your kickdown switch. Maybe using parts from your 2bbl carb.
Q2: Edelbrock has a fuel line kit (#8135) that consists of a rubber hose, some fittings,a filter, and clamps. In addition, you will most likely need a banjo fitting (#8089) to allow clearance for a low profile air cleaner. There are no hard line kits. You will have to make your own hard lines if desired. Tube bending and flairing can be fun! If you use a rubber line, route it away from heat sources to avoid percolating you fuel, or fire danger.
Q3: If the manifold does not have a vacuum fitting, then there are three provisions on the carb for vacuum. Looking at the carb from the front, there is a large port in the center of the base. This is your PCV port. This is critical to keep crankcase pressure under control so that you don’t get oil blowby at the rings. To the right of this is a smaller fitting. This is a full time vacuum port. To the left (I think) is a ported (part time) vacuum port. Most distributors use this port but you must verify that this is the type of vacuum needed by you. Cap off the unused port so that you won’t have a vacuum leak.
Q4: 2 options. Get rid of the tube and put a breather on the valve cover opening. Or knock out the plug at the bottom of the aftermarket air cleaner, get a fitting (from any performance section of your parts store) for the hose and route it there. If you use a stock (4bbl) air cleaner, then use the hose as in stock configuration.
Q5: I can’t recall their function. I’ll check my user manual. You might also contact Edelbrock on this.
A: Any 4bbl air cleaner will work as long as the carb neck is the same (most are universal). Look for one that the intake neck is on the same side as your current cleaner. Look at a second gen firebird, should be close. be careful the one you pick isn’t too tall. Compare with the original and if taller, close hood SLOWLY to be safe. If you chose well, most people will not have a clue it’s not original. This would get you by until you can find an original.
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Content last modified: January 15, 2014 at 1:24 pm
Q: Kick Down Switch
Where did you get this switch? I’ll have to double check, but I’m almost positive that mine is missing… and will need that with my 455! Just wondering where I can find it?
A: The part is by BandM, Summit part no. BMM-20297. It’s listed on page 159 of Summit’s catalog that was good through June 30, but you’ll have to check the web for a picture. Just search with that part number at http://www.summitracing.com.
The kit is intended to be used with an existing TH350 bracket when you swap in a TH400. I already had a TH400 and no bracket at all, so I had to fab a mounting bracket and a small piece to attach it to the throttle. Not tough if you’re handy with tools. The linkage is adjustable and very forgiving for differences in mounting methods.
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Content last modified: January 15, 2014 at 1:27 pm
Q: Throttle Kickdown Switch for 1968
Can someone provide me with the GM part number for the kickdown switch for a 1968 coupe 400/TH400?
A: the part number for the kickdown switch is:
#9785545 (same…. 65-66 P/8 M-40, 1967, 1968, and 1969 F/8 M-40)
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Content last modified: January 15, 2014 at 1:30 pm
Q: Throttle and Kickdown Hookup for 1969
Anyone happen to have a picture of how the throttle and kickdown cables hookup to the bracket and the Carb Lever for a 1969 4bbl with TH350? How about a good description? I’m pretty sure I have the throttle cable right but I’m not quite sure how the TH350 kickdown cable hooks up.
A: The kickdown cable snaps into a square hole on the carburetor side of the throttle bracket. If you don’t have the exact bracket you will have to improvise. A 2bbl one will not work, the cable will be 3/4″ short of the carburetor bracket. The reproduced ones for $80+ are for 1968 and don’t have the necessary square hole for a TH350. If you find a source for a four barrel cable mounted throttle bracket with the TH350 kickdown hole, let me know.
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Content last modified: January 15, 2014 at 1:31 pm
Q: Firebird Throttle Cables 1968 / 1969
I need help finding a throttle cable for a 1968 400. What one is correct?
A: Well, it seems there are some out there selling NOS cables as something they are not.
INFO I’VE DISCOVERED (*thanks to all who’ve shared*)
ORIG. GM PART NUMBERS:
9792222 1968/1969 F-6 1Bbl, F-8 2Bbl ***YELLOW TAG*** Total Length End-to-End: 19.5" Case Length: 13.5" (((This one is apparently still avail. from GM for approx. $25))) 9792223 1968/1969 F-6 4Bbl ***BLUE TAG*** 9792224 1968/1969 F-8 4Bbl ***WHITE TAG*** Total Length End-to-End: 18.0" Case Length: 12.5"
Now, in order to confirm all of this, it would be nice if any owner’s could measure their cables/cases. This includes all of the above… 4Bbl V-8, 2Bbl, 1Bbl I have a few pictures that I’m trying to get on the Generation-1 WebSite for comparison but AOL has been a real annoyance lately in updating info. Anyhow, if the updates come through, they’ll be at the following site:
http://members.aol.com/Framair/TechTips.html
Thanks again to all who’ve helped out on this one. Sharing this sorta information will help to educate all of us (me included) on ‘Bird Parts.
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Content last modified: January 15, 2014 at 1:34 pm
Q: Gas Tank Sending Unit
I’m replacing the gas tank on my 1968 Firebird 400 and have located a sending unit. However, I’m being asked to select between a one or two tube unit. Can anyone help me with this selection without first removing the gas tank ??? I’d like to have all my parts before I remove the tank.
A: Look under your car near the front of the gas tank. If there are two lines coming from the take you need the two tube unit… If one line, the one tube.
A: There is multiple ways you can tell which sending unit you have in the car right now. The fuel lines connect to the sending unit on the right side of the tank new the front of the tank. Now, look there and see if you one or two lines coming back from the engine compartment. Cars with two lines require the two line sending unit, (one line is fuel, the other is a vapor return. If you don’t want to crawl under the car, look under the hood a the fuel punp. If you see THREE connections on the pump, you need the two line sending unit. (Connection 1 to the carb, connection 2 is the fuel line from the tank, and connection 3 is the vapor return line to the tank). If you see two lines connected to the fuel pump, you need the one ine sending unit, (Connection 1 to the carb, connection 2 is the fuel line from the tank.)
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Content last modified: January 16, 2014 at 6:10 pm
Q: Throttle Cable Bracket Codes for 1969
I just bought that bracket off eBay and think it may be the wrong one. It appears to have an F2 on it and someone told me he thinks the 1969 firebird 4 bbls have an F4 on em. Is there a difference for automatic or sticks?
A: The Throttle Cable Bracket fromE-Bay Auction is for a 1969 Firebird 2Bbl application. The “F2” designates 2bbl. The correct Bracket for a 1969 Firebird 4Bbl is 9797415 which is stamped with “F4” (for 4Bbl).
Since we’re on the subject, sometime in May of 1968, a new Intake Manifold and Throttle Cable Bracket for the 4Bbl Firebird came into production.
Intake manifold: 9794234
Throttle Cable Bracket: 9797415 (F4)
This Manifold was used on late model 1968 Firebirds, GTOs, Full Size models with 4bbl Carbs. Also used on all 1969 models with 4Bbl.
This set-up superseded the previous manifold/bracket… 1968 Firebird (1st Type up until May of 1968)
Intake Manifold: 9790140
Throttle Cable Bracket: 9792242
I believe that the Throttle Cable Bracket you’re looking for has been reproduced.
There is no difference in Throttle Cable Brackets for Automatic/Manual Trans.
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Content last modified: January 15, 2014 at 1:35 pm
Q: Fuel Sending Unit
I’m in need of a two tube fuel sending unit for my 1968 Firebird 400. Does anyone have a used unit for rebuild ? Suggestions for locating a unit ? What was the original part number ?
A: The original part number for the 400 Firebird Fuel Sending Unit was…
6427857 Gauge, Fuel Tank Unit (Sending Unit)
1967-1968 F/8 w/A.C. and 1967-1968 F/8 “400”
This is from a 1969 Pontiac Parts Book.
Big diff. between this and those being sold as replacement units is the Vapor Return tube.
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Content last modified: January 16, 2014 at 6:11 pm
Q: Throttle Cable Bracket Replacement
I am changing out the intake manifold and the carb on my 1968 bird and it seems that the throttle bracket would have to be replaced. The intake is an Edlebrock Performer and the carb is an Edlebrock 600 cfm non egr carb… the stock carb is a 2bbl. i wanted to know if anyone has fit one of these carbs on their bird, and what kind of throttle bracket they used. The stock bracket seems to short.
A: I just did the exact same thing. I installed the Edelbrock Pontiac Performer and the Edelbrock 600cfm carb. I did not have the old original throttle bracket to begin with; just some old homemade bracket that was used on the Holley carb previously on there. The Holley throttle linkage sat much lower and I could not reuse the “homemade” bracket with the new Edelbrock carb.
What Edelbrock tech support says to do (after I was on hold for 15 minutes) is not quite the right thing to do. They say you need to purchase their Throttle Bracket–Pontiac (’68-’71) P/N #8015 . When you order this and get this, it has instructions telling you how to modify your old original throttle bracket!! Drill here, bend here….NONSENSE! It looks funny AND I did not have one. Besides, the original throttle bracket goes for $75 at Ames! I could NOT BELIEVE that they did not have a universal throttle bracket solution to their own manifold/carb combination!!!
The answer is to order a Lokar (brand) steel braided 24″ throttle cable and throttle cable bracket (sold seperately). It goes in nice and easy and looks ever so sweet! The Lokar throttle bracket comes with dual throttle return springs. All of it is stainless steel. I found it locally but I believe that Summit Racing sells the same thing.
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Content last modified: January 15, 2014 at 1:36 pm
Q: Removing Fuel Sending Unit
I have a leak around where the fuel lines come out from the fuel tank. How do I remove the fuel tank sending unit? Do I need a special tool?
A: You don’t really need a special tool to remove the sending unit lock-ring. First clean off the area around the unit, (I like to use a shop vac and a brush). The ring should have 3 or 4 tabs; using a small brass drift, tap the ring around to the un-lock position. I try to use the tabs evenly so as not to distort any 1 tab. When removing the s/u, do so carefully, the filter element is usually fragile with age. Under the sending unit flange is an o-ring. Make sure this isn’t damaged and clean prior to installation. In my case I had a gauge problem and decided to repair and replace the s/u. I couldn’t find a new or rebuilt anywhere. So, disassebled it and carefully cleaned it and it has worked fine ever since.
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Content last modified: January 16, 2014 at 6:12 pm
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