go to the holley and crane cams web sites, they have good web tools to determine the good mix of parts, think of the carb as the lungs, and the cam as the brain, even though your brain sais breath, if you have cold sometimes the lungs don`t co-opperate. An engine is a system, where every part affcts the other, too much carb for the cam or too much cam for the heads will make an engine worse, not better.