Carb flow rate?

[AnlaufJohn]

My 1966 C-10 has the original 283 V-8 with 2 bbl Rochester 2G carburetor.

I picked up a spare 283 long block and SM-420 tranny a couple weeks ago, and am tearing the engine down to have it checked for cracks and such. If it's good, then the heads will get new seats and then will be set aside.

My question is this: will the 2G carb flow enough to support my ideal rebuild of a 300 hp engine? I have used the calculators at several sites and my guess is I will be needing 420 cfm, give or take 20 cfm.

Where does a stock 2G Rochester fall? Too little cfm or just enough? I don't know if it has enough to reach the 5000 rpm limit I am looking to strive for.

Thanks in advance for this forum's collective wisdom.

AnlaufJohn

[blackedoutharley]

Asking a 283 with a stock 2 barrel to achieve 300 hp is a tall order. I think that you will find the Rochester 2G to flow approx. 350 cfm.

Unless you're racing it I think you will find developing torque to be more beneficial to horsepower.

[skoffice]

Originally Posted by blackedoutharley

Asking a 283 with a stock 2 barrel to achieve 300 hp is a tall order. I think that you will find the Rochester 2G to flow approx. 350 cfm.

Unless you're racing it I think you will find developing torque to be more beneficial to horsepower.

Well said. I'm sure the HP level can be reached with a 2 barrel but likely not with that carburetor. If you can get a good cam in it you should be able to make some nice power with even a Holley 2 barrel. Do you want to stick with the Rochester for any particular reason?

[AnlaufJohn]

Well, that's a good question. I know of a good, clean Edelbrock Performer intake for $70, but then I need a 4 bbl carb. I understand the pros and cons of 2bbl vs 4bbl, regarding economy and available power.

When I look at the info from the GM Heritage site, the 327s came with a 4bbl 4Jet that I may be able to acquire from a friend. I am going to try to stay away from the Edelbrock/Holley carbs, based on some discussions on the 67-72 board forums.

If 350 cfm is the estimated max of the 2G, then that is what I needed. Now I can discuss this project with Jack, a friend from work, who is helping me with the planning of this long term rebuild.

Thank you so very much,

AnlaufJohn

[TwoFiftyShifter]

Once the motor is warmed over, theres a ton to gain going to the Q-jet from the 2 barrel, its definitely worth it.