# 1964 GTO 4speed carb cfm?



## JWatkins (Dec 11, 2010)

I have a 64 GTO 4 speed, 4 barrel, 389 and I don't have the stock carb on it. I researched a lot of web and threads, thinking this would be an easy question to find an answer for, but I was wrong. I find that the stock carb was probably a Carter AFB, but don't know the proper cfm for the 4 barrel? I know this is subjective, but is the Carter of the proper size the "best" way to go for smooth performance in a stock motor? Thanks,
Joe


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## BearGFR (Aug 25, 2008)

JWatkins said:


> I have a 64 GTO 4 speed, 4 barrel, 389 and I don't have the stock carb on it. I researched a lot of web and threads, thinking this would be an easy question to find an answer for, but I was wrong. I find that the stock carb was probably a Carter AFB, but don't know the proper cfm for the 4 barrel? I know this is subjective, but is the Carter of the proper size the "best" way to go for smooth performance in a stock motor? Thanks,
> Joe


If you don't care about "original" it's tough to beat a well set up QJet for the street on that size motor. I know that the original Carter was also a spreadbore carb, but I don't know if the bore size and spacing on a QJet is the same and will work on the 64 manifold. Carters are good too, though. At 600 cfm they don't move quite as much air as a Qjet (750 cfm) but still would probably be sufficient for a stock 389.

Bear


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## Koppster (Jul 27, 2008)

I agree with Bear, if you're looking for performance vs originality the Carter might not be the best solution. Quadrajets, especially those rebuilt by Cliff Rugles (sic) are very popular and folks rave about them. 

Cliffs High Performance Quadrajets :: Qjet Carburetor Rebuild Kits, Parts, Quadrajet Rebuilding, Quadrajet Parts, Bushing Kits, Carb Tuning

Another solution is to consider an Edelbrock carb, cheaper than a Cliff Rugles Quadrajet and a pretty reliable carb. The Edelbrocks are for all intents modern remakes of the Carter AFB design.

If your 389 is stock, an Edelbrock 600 or 750 would probably work fine:

Edelbrock.com - Carburetors & Accessories - Performer Series Carburetors

Rick


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## Koppster (Jul 27, 2008)

PS, here are some PY posts that talk about AFB CFM:

Original AFB CFM? - PY Online Forums

Carburetor comparisons - PY Online Forums

Pontiac AFB carburetor part numbers

Pontiac Carter AFB carbs - PY Online Forums

The last thread is really helpful, if the data is correct the original AFB for your 64 the CFM was probably 575.

Rick


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## geeteeohguy (Feb 2, 2008)

I agree with Rick. If your car is otherwise stock, an original AFB will bolt right on and work very well with your combo. A Q-jet would need a Q-jet type manifold to work well, and that may be an issue with a '64 block, as the intake pattern was changed for '65-up.


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## JWatkins (Dec 11, 2010)

Thanks all. I am in the hunt for a new carb and will take all of your information and see what I find.
Joe


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## Willshire (Jul 14, 2011)

I know this is an old thread but can you adapt a qjet to the original manifold? Will it dog the performance of the qjet by doing so? I can get a free qjet from a friend, rebuild it and run it on either a ep4! Or stock iron intake. Thoughts?


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## freethinker (Nov 14, 2009)

Willshire said:


> I know this is an old thread but can you adapt a qjet to the original manifold? Will it dog the performance of the qjet by doing so? I can get a free qjet from a friend, rebuild it and run it on either a ep4! Or stock iron intake. Thoughts?


you would need some kind of adaptor to put a qjet on a stock 64 manifold. quadra jets are a variable cfm carbs. they are designed to work on everything from a 6 cylinder to a 455.


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