Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked on First Generation Firebird-L mailing list. Special thanks needs to be given to all the Firebird-L owners that took the time to respond to other subscribers questions. These pages are continuously updated as new information is posted on the mailing list.
|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.|
You are correct in the reference to a "400 Sport Option".
It is mentioned thruout the parts catalog and even in the
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.
|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.|
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.
|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.|
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.|
|Q:||400 Rebuild Suggestions|
I HAVE 68 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
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 Chevy Hunting!
My new 68 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.
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*
|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.|
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???
Regarding tips for more horsepower, if youve got some money:
We went with a set of those aftermarket edelbrock heads for several reasons:
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.
|Q:||'69 350 Motor Mounts|
Earlier I was asking about the Motor Mounts for a '69 350, and I told you when I found out FOR SURE I'd give you an update.
The Anchor book is WRONG. The '69 350 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.
|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.|
|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?|
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 67 and 68 Pontiacs (as well as the earlier engines) used an 8 bolt timing cover and pump. In '69, 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 '67 and '68 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.
|Q:||V-8 Into a 6-Cylinder Compartment|
|I have a 400 block built and plan on putting it in the '67 326. I was wondering what special bracketry I mich need to accomplish this.|
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 '67 accessories or brackets with any later stuff. You will risk pulley alignment problems.
|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 '69 327 from a Vette but I am not sure it will bolt in as is. Can anyone advise?|
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!|
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.
|Q:||Small Block Chevy in a '68|
|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?|
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 '67-'69 Camaros used a rod linkage for the throttle, as did the '67 Firebirds. The '68 and '69 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 '67 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!
|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.|
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.
|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 67 400 I used this spec and had no problem for the 10 years I drove the car after a rebuild.|
|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?|
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.
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
|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.|
|Q:||Oil dipstick tubes for the '68 400|
|What is the correct tube for a 400?|
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.
|Q:||Dipstick Problem after Rebuild ('67)|
|I just rebuilt a 326 Pontiac motor to put onto a 67 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.|
|Q:||Oil Spraying out of Dipstick|
I just recently purchased a 67 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.|
|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 67 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 67 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.|
|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.|
|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 68 400 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.|
|Q:||'68 Firewall Difference Between AC and Non AC|
|I've been working on my '68 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?|
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 69 400 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.
|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 68 with a cast iron waterpump. I understand the timing chain covers and waterpump on 69 and later are different. Does anyone know if these are interchangable?|
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|
|Q:||Low Oil Light on New Engine|
Just started the new motor in my 68 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?
I don't know if this is your problem but it is one thing to look for from my
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.
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.|
|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?|
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.
|What oil is recommended for my '68 engine.|
My '68 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
|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.|
|A:||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.|
|Q:||Voltage Regulator Mounting on a '67|
|Could somebody please look at their 67 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.|
|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.|
|Q:||Spark Plugs on '68 - #8 plug inaccessible|
|I have a '68 400 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 '68/350 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.|
|Q:||Cam for a '68 400|
|I'm trying to track down the stock spec's for the cam in my '68 Firebird 400 conv. It has no performance upgrades that I am aware of, any help? Lift, duration, lobe sep, etc.|
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)
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).
|Q:||'67 Heads (061's)|
|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.|
The '67 061'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..
|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.|
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:
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 68 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 68 YS block (GTO/big car) in my car came with these heads. After reading McCarthy's comments, I decided to hang on to them.
|Q:||Speedo Cable Mystery for '68|
During the course of researching codes for the '68 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 '68 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.|
|Anyone knew how to disassemble the '68 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.)|
|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.|
|I have a 68 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?|
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.
|Q:||California AIR system|
|I have a '67 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 '67 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.|
|Q:||Runs Great then Quits|
My problem is my 68 - 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.
Note: Dwell & timing stay perfect. Anyone out there with an idea.
|A:||It sounds like you've been guessing instead of diagnosing, Cork. 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.|
|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.|