How much carb is enough?? Too much??

    There are many CFM calculators and such on the web. Do a Google. When I put stock K code figures in, a 600 CFM carb is not justified. More like 450-500 CFM. With a High Rise manifold and such, a 289 still only needs 500 CFM.


    So what's the deal? Why does a stock K use a 600 CFM carb, and a GT350 uses a 715?!? Isn't it way too much carb, which ultimately hurts performance?


    My fastback (Not a K) has a Holley 4150 650CFM double pumper. Engine built similar to GT350 spec. Just wondering if it would work better with a much smaller carb.

    You will likely get a lot of answers to this one, but one of the reasons that Shelby used the Holleys was the center pivot float bowls for cornering.

    Smoother running, crisper transitions, and better economy would probably be obtained with a 600 cfm or smaller vacuum secondary carburetor. People don't think a Ford carburetor in either of the 1.08 or 1.12 sizes is very glamorous but they are one of the very best designs of all time.


    Back in the 1970s a friend of mine drag raced his Mustang with a finely tuned 1.08 model and did very well in the stock classes.


    Dan

    My 715 cfm Holley was unsatisfactory due to an off idle bog. I had Pony Carbs restore it, and specifically asked them to do whatever they could to eliminate or reduce the bog. Don't know exactly what they did, but the result was amazing. Now it operates like a smaller carb on the low end and a large carb when the rpm is higher. Best of both worlds now.


    Z. Ray

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