Originally posted by camaro_fever68
I'm running a set of Iron Eagle 215cc on a 420cid small block chevy and I love em. Out the box peformance. The engine your building is going to be an awsome torque monster. I don't think I'd drop to a 600 holley though. I think your doing good with the 770 vacuum secondary. Should work out perfect.
Here is a formula for carb. sizes.CID X MAX RPM DIVIDE BY 3456.Based on this formula you would need around 627 cfm.This is based on 6,200 r.p.m.s. max. rpms.600 is much closer than 770.