Thread: Carburetor for 327

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Hi,

My 68 327 still has its stock Rochester Carb, and it has seen much better days. I want to replace it with the 0-Holley Street Avenger 670CFM 0-80670, but I am unsure how well matached this would be. Currently the engine is still stock, but as I get cash I am planning to upgrade.

Any suggestions?

I'd say for a stock engine the 670 is going to be too big of a carb.... Something in the 570 to 600 CFM range would probably work a lot better. Are you changing intake manifolds, too? Not sure, but was the old Rochester the same bolt pattern as a Holley, or was it smaller???? Hopefully one of the chebbie guys will remember.

My 68 327 still has its stock Rochester Carb

What was the CFM rating for the 4bbl Rochesters?

anything larger than a 600 and it will be stumbling all over itself. i would go with the 600, still a little large but a tunable carb for your stock motor. that way if you do upgrade the intake, and headers. you will be right where you need to be with the carb.

The flow ratings for the rochesters was 600 CFM for the small blocks and 800 CRM for thje big blocks. Also the rochester is a spread bore type of carburetor whereas the Holley is a square bore type. So if you want to run a Holley you will either have to change to a square bore manifold (recommended) or use an adapter plate. Adapter plates restrict air flow and also raise the carburetor and can cause hood clearance problems. Also if you are using the stock air claner you will have to replace or modify it to fit a holley's top air horn

Is it the old 4GC Rochester, or the spread bore Quadrajet on the car????

Thanks

I believe it is currently a spread bore Manifold. I am planning to replace it with a square bore instead.

oh well, since the 670cfm will be to big, maybe a Holley 0-1850S 600CFM instead with an Edelborck TorkerII manifold

Actually, I reckon the Holley Street Dominator 300-38 manifold will be better for my application

I've had some good experiences with the Edelbrock Performer RPM intakes, too. The cam that matches the intake works good, too. I think the 600 Holley would probably be a good choice for the car.... Have fun with your project!!!

IMO the 670 Holley is not too much carb with vacuum secondaries. Some of it depends on the weight of the car and rear end and cam etc.

If you go to the Holley site it will recommend it ...........

Kitz

Originally Posted by kitz

IMO the 670 Holley is not too much carb with vacuum secondaries. Some of it depends on the weight of the car and rear end and cam etc.

If you go to the Holley site it will recommend it ...........

Kitz

I agree with kitz.

Originally Posted by ZAFluffyBunny

Hi,

My 68 327 still has its stock Rochester Carb, and it has seen much better days. I want to replace it with the 0-Holley Street Avenger 670CFM 0-80670, but I am unsure how well matached this would be. Currently the engine is still stock, but as I get cash I am planning to upgrade.

Any suggestions?

I would try a 525 Barry Grant or a 500 cfm Edelbrock.

Big Barry Grant fan myself, never used the road demon jr, but have had nothing but good luck with the road demon, and speed demons, I'd go with the Jr.

I swapped out my ole Carter for an: Edelbrock-Performer-600-cfm-Carb-Electric-Choke;

http://www.martelbrothers.com/catalo...ctric-Choke-p-

Picked mine up a SHUCKS on sale - $ 239.oo ( You have to buy their Fuel filter kint ( which takes away any perceived discounts, though )...
...feels like a completely different truck, 327, mild cam,

The Barry Grant carb ain't a bad choice either. Most any reasonable vacuum secondary carb won't bog though and it'll draw what it needs when you get it on ..........


Yeah, well I'm a Holley dude. That said I've got an 850 vacuum speed demon on my 502. And God willing one of these days my left arm is gonna get a little better and I'm a gonna' get her goin'. If'n I don't like the Demon, well, I'll let you boys know

Kitz