I know that this is not the carburetor section, but I wasn't getting much of a response there. So, I'd like to try here. I've decided to upgrade to a Carter Competition series 9625 (625 CFM) to feed my warmed-over (headers and Isky cam) 340 SBB... mainly because it was free. While doing some background I've found that the equivalent Edelbrock (1406), has the same size Venturies (1 & 3/16" P. and 1 & 9/16" S.) and Bore diameter (1 & 7/16" P. and 1 & 11/16" S) but it's only rated at only 600 CFM. Anyone know why the Edelbrock is rated at a lower CFM? Thanks,
