Ok Team..

I have a 1969 FGF 350 2bbl, Auto, non air car. We have completed most all and NOW we have some engine issues. I have a lower end knock that I believe is the rod, a carb issue, coil and ignition issue to state a few problems. Compression is good at 160-165. It runs very ruogh and now need to use both feet while driivng. I have spoken to the previous owner and have the car documented back to 1978 with no major engine work done. I really do not want to keep throwing money at the engine and believe that I should just rebiuld the engine. I do not want to drop a chevy in her.

I live in the SF Bay Area and was planning on having Diablo Engine and Machine do the work but found out today that they are no longer in business after 45 years. They were reasonable at $1900.00 for the rebuild plus $1000.00 to pull and reinstall. Thats a few buck! If I was handy in the engine compartment I'd do it myself but have never done a rebuild.

What do you all think? Do any of you know of a rebuilder in the area that is reasonable or any other ideas to help with my decision.

Garz & Son
1969 Firebird 350

$1900 for a rebuild is good but the $1000 for pull and install is where you can save yourself some money. That part isn't hard and requires no special expertise.
Did you know that the going rate for a really nice rebuilt, era correct, 400 is only $3000? Save yourself the $1000 and use it to upgrade to a freshly built 400.

I may get flamed for this one, but why not rebuild it yourself? Engine work is not voo-doo magic.
A straight forward overhaul is not all that difficult. Yes you can get anal about everything inside, and some would suggest anything less than el-perfecto is a waste, but to just replace bearings and rings and a valve job is pretty common stuff.
Many, many engines have been rebuilt by first timers. (not sure if that applies) But as long as you pay attention to detail it'll work out fine. A old block doesn't always need bored, might just need some clean up of the ring ridge. Your compression seems fine so unless you plan on racing it a stock rebuild should work.
The running rough part probably has nothing to do with the knock, mosts likely carb and ignition. But pull a valve cover off, you might just have a bent pushrod of rocker stud off.

Install a factory quad intake and better carb if you want during rebuild, but the thing ran for how many years as a stock 350 2 barrel?
Or for what you'd save with DIY you could upgrade the intake, ignition and exhaust all at once.

Just my 2 cents.

I would build a 400 and learn how to save yourself $1000 on a 4 hour R&R of a motor. I charge $200 for R&R of a motor. 1.5 hours disassembly and 2 hours re-assembly.

$1000 is outrageous.

You can run a 4 barrel carb on a 350, but not with a 2 barrel cam and heads..NO!

A 350 will cost you 3-500 more to rebuild than a 400. Find a 67-71 400 core, rebuild it and swap over all your brackets, accessories and pullies.

Depends on what you want to do to the 350. Pistons for a 350 are getting hard to find (especially if you want anything more than an 8 to 1 compression cast piston.) Been there, done that!

No flames from me, but at the same time, if someone that isn't familiar with engine work should just by chance overlook one simple aspect of it, there could be major headache and additional time & costs involved.
I whole heartedly agree that the problem may not be a bad as originally perceived and pulling that valve covers would not hurt.
If, however that compression is that equal all the way across, I doubt you'll find a problem with the push rods or rockers.
As Jim points out, it's not THAT big of an issue to remove and replace the engine and the money you save could be put toward...
And if you're looking for performance as well as reliability, man those 400's are hard to beat.

Garz, Tri-Valley can do the machine work if you decided to DIY. I've heard more good about their work than bad so they're are probably safe and very local for you(Pacheco). As far as r&r the original motor, I know a shop over here in Rodeo that has a good rep. Probably about $2500 for the whole job(just a guess) and the good part is he owns a real nice 67 coupe so he'll probably do a good job.
On the other hand if it was me I'd find out why it running rough before I went to all the time and trouble. It might be a cheap fix like a new dist cap or points or carb rebuild(water in the tank). Could be any number of easy fixes.

Robert

I agree with everyone. Although I didn't want to rebuild the engine my self for the simple fact that I haven't done it and didn't want to miss something. But thats what friends are for.

But especially the R&R, definately do that yourselves. Get a couple buddies, preferribly the automotive type and go slow. Its pretty straight forward. Take a bunch of pictures to help on the reinstall.

Good luck.

Robert,

I'd like to know more about the guy in Rodeo your talking about since he's so close.

We planned to attack it with the carb rebuild or change out, drop in electronic ignition, change the coil (needs to be done) However the knock has me worried, if I need to get into the engine I might as well just go for it and be done with it....is this crazy...just seems to me that I remember some of the other projects....few buck here...few bucks there and eventually your doing it anyway......

But then again all of use really are doing this for the love of it...or to get away from the other half....it's sure isn't the money!

Garz & Son

Sent a PM

Robert

Not to steal the thread but could you (Banshee) explain your comment on not running a 4 barrel carb on a 350 with 2 barrel heads and cam.the reason i'm asking is that is how my 350 is set up.i'm not a engine guru so just looking for your reasoning,maybe something i should look into in the future.

You can run a 4bl on small heads and cam.
Your gas milage will also increase if you stay out of the secondaries.
Primaries on q-jets are smaller then 2bl carbs.
And will take the secondaries fine. May need to set the tension spring on the upper air plate to open later(slower).

R @ I'n an engine in a 1st gen is a breeze after you've done a few times.
Takes me about an hour by myself. Course i know what tools and have a procedure.
1st timer could probly do it in 2-3 hrs.

Can you run a 4 barrel with a 2 barrel cam and heads?

Yes, but why?

Why not run a 2BBL on a 350 HO motor?

We have been over this time and time again. A majority censused first reply why? and the second is for what reason.

Build the motor the correct way and save headaches. Some people here have many years behind their belt and some do not. One who asks the 2/4 barrel question usually has little knowledge on the matter, thus, I always ask why. I would never ask a person who has never built a motor to build me a motor.

I look at the big picture here on the 2/4 swap. Most people are thinking that if they do the swap, their car will be helluva lot faster...this is the mentality. When they get piss poor results, they ask "why"? That is why I say NO on the swap...most people assume result X and only get C. There is way more to this question than a "simple" or "compatible" swap. It is the human perception of the unknown result. I know the general end result of the motor in most cases and know from over 20 years of hearing people doing the swap and their attitude and displeasure with the result.

Do what you want, you will anyhow. I say it is a waste of time and money. Wheras, for $500-700 more (proper cam and heads) you can do this correct.

To further the commentary..Most guys do the swap for what I call "cool points" and without looking at the impact. Most 2 barrel cars, I guess have highway gears..mid 2's very low 3's maybe.

You put a huge carb on a motor. (whether or not you can tune a carb, irrelevant)

Brent brought up the point on a post about exhaust that a motor is an air pump..of course, it is. I'll break this fact down in sort of laymans terms. I will assign a number for each motor part within this air pump.

Carb, 4 barrel #7
Intake 4 barrel #7
Cam, 2 barrel #4
heads, 2 barrel #4
exhaust 2 barrel #4
rear gear 2 barrel #4
trans gearing #4 (maybe the same as a 4 barrel though)

The trans and exhaust size/configuration may be different for a 2 barrel car. Maybe they got single outlet or duals with smaller pipes over a 4 barrel car. I know my 96 TA 8 cylinder had duals and a 96 Firebird had a single outlet. The trans ratios may be different, but I really have not had my eyes in any big car or 2 barrel research.

Those numbers sort of (basically) reflect air flow in a motor. Why increase airflow at the top to only bottleneck or restrict airflow within the motor in theory. Will the motor run? sure it will. It is to what efficiency and temperment that it does.

Most 2 barrel heads have 1.96 heads and 1.66 exhaust. A great example is 1969 #47 heads (350) #48 heads (350HO and RAIII 400). The 47's are 72 CC 1.96/1.66 valves and press in studs. The #48 for a 350 are 65 CC and 2.11/1.77 screw in studs. The #48 400 heads are 2.11/1.77 72 cc and screw in studs. The 47's are 2 barrel heads, the #48's are 4 barrel. The difference between the two is intake/exhaust size and press/screw in studs. The 47's can be converted to 2.11/1.77 and tapped for screw in studs and you could have a set of RAIII heads. The machining costs to convert far outweigh locating the proper heads.

The 254 cam had a duration of 269/277 and that was used both on 350 and 400 motors with 2 barrels.

I may be blowing smoke, but..mismatched engine components will work, but at what overall effect?

I agree to a point.
Depends on what a person's goal is.
If it's to be faster, then no, it's a waste of $.
If it's to get better milage, then it's not.
Well known fact that q-jet's get better milage on street AND highway.

Just so you know how i really feel about it.
My cars all have nothing less then 400c.i., 2.11/1.77, 75cc's, 744 cams.
Then there's the one i'm building for the 68FB.
440c.i.(4" crk), 2.19/1.71(315cfm), 66cc's, rllr cam, GRP rods, Ross bttn pistons, etc.
700hp N.A., plus a little n2o.
Street car? When i can afford to fill the 20g fuel cell with 110 octane...lol

Forgot.
I beleive a good dual exhaust is a must also.
With or without a 4bl.

In NASCAR restrictor plate racing, these motors have the capability to run 40 HP more and upwards of 200 mph plus, but plates between the carb and intake limit HP. These plates slow down the amount of fuel and air to the motor, limiting them.

This 2 barrel to 4 barrel swap is the reverse of that, generally speaking.

your right i now very little about engines,but since my car is a 350 2 barrel with a 4 barrel carb (by previous owner) i had to ask after your comment. my car is just a cruiser not going to the track.eventually i would like to improve on this.this forum is for learning and helping,that is why i asked someone with more knowledge.

Harry

There are no drawbacks by putting a 4 bbl on and engine, regardless of valve size or compression, i would use a q-jet as long as it's jetted right throttle repsonse and gas mileage will improve as well as overall horsepower.

I disagree.

One drawback is the expectation of performance increases.

I ran a 400 with a set of 46's and a 4 barrel over a set of 5C's. Yes, it ran better than the 8-1 5c's, but not as well as it would have with a set of larger valved 48's, 12's 62's, 16's or 670's.

Pontiac did have engineers working on this.

And the others..Pontiac could have saved a ton by using small valve, pressed in stud heads on all their motors, but did not. I know of one large valve pressed in stud head..061 1967 one year only..and it was nixed.

Off track, but if there were no drawbacks, Pontiac would have used small valved heads and pressed in studs across the board, even for performance motors. This thought is reversed with placing a 4 barrel on a two barrel motor, but still applies.

So a 500 cfm 400 CI motor with an engineered cam for that application will run properly with a tuned 750 cfm 4 barrel carb and intake..I agree. Pontiac should have applied 2 barrels across the board to save money?

The reason you have carb A with Cam B with CI motor C with Head D is overall HP potential and effectiveness of said combination.

Would you put RAII or RAIV heads on a 350 motor with a 2 barrel carb?

Just throwing out some rhetoric...

Some more rhetoric, 2 bbl carbs and intakes were put on at the factory for one reason, to save money! The bean counters often ended up coming up with the packages, not the engineers!

I'd rate the 2 bbl as the major restriction on a 2 bbl engine, followed closely by a single exhaust - maybe the other way around depending on the engine. The intake and heads aren't very much different from the 4bbl components in flow capability, espcially if you can convert a set of #47's to the level of #48's with bigger valves and screw-in studs. Personally I wouldn't bother with the big valves in a 350 sized bore or the studs, because the added expense wouldn't add much performance. I've built and dyno'd enough engines for restricted 2 bbl and small 4 bbl classes to know how much each of the parts adds to the power, and I was very close to building a Pontiac 2 bbl 350 that would have
killed the SBCs.

Incidentally, a switch from a 390 cfm Holley to a 750 on a 500 hp engine will add about 60 hp, and the NASCAR restrictor plate engines are down a lot more than that from the unrestricted engines!

My thoughts: change from a 2 bbl to a Q-jet, maybe step up a bit on the cam specs (an RV-type grind with about 210/215 @.050" and .420" - .440" lift), install a dual exhaust and decent mufflers and you'd go from about 250hp (on a very healthy 2 bbl 350) to about 280-290hp with no loss in low speed performance or drivability and very likely 1-2 mpg better fuel economy especially with the granny gears!

The only reason for the existence of 2 bbl set-ups with smaller valves, no screw-in studs and single exhausts systems was to provide a cheap alternative to a properly coordinated package. If the real goal was to increase fuel economy instead of just to cut costs, a better engine combo would have been a torquey V-8 built for under 4500 rpm operation with a vacuum secondary 4 barrel carb that has very efficient primaries, with slightly smaller intake runners and cylinder head ports, about 9.5:1 compression max for pump gas, mild cam, free flowing exhaust and tall gears - hey, that all sounds familiar!

Not to promote the Brand X engines' philosophy but very few 4 bbl SBC's received valves as big as the Pontiac 2 bbl engines. Only the top level performance engines got the 2.02" valves.

Performance expectations: the reality is sadly exactly what Tom has stated. When people put on a 4 bbl intake, better cam and exhaust system they have the expectation that they will be able to feel the difference. Properly set up with a mild coordinated package, the engine should make at the least the same if not slightly more torque in the lower ranges as before. The big improvement however is that the engine will be able to continue making good torque at higher revs than before. This doesn't change the seat-of-the-pants feel of acceleration that most people expect but it does improve the overall performance of the car.

Sorry Brent, meant to say 400 HP more...NASCAR restrictor plate (depending on specific track and plate)

Yeah, that's more like it!

Back in the late eighties Road and Track did a top speed comparison between the mighty Porsche 917 LeMans car and a good ol' boys Winston Cup car. They let both teams do what they could with adjustments and duct tape. If I remember right the twin turbo Porsche almost touched 220 mph. The Buick Regal bodied Cup car with the non-turboed 355 small block? 240 mph! I'd like to see that done again with the new bodies and the extra 200 hp they're getting now!