650 or 750 cfm. carb??

JoseyWales said
When selecting a carb for a street motor Ive always used a volumetric efficiency formula which is (cubic inches x max rpm)divided by 3,456 = carb cfm. Its always worked very well for me. Once you do the math, round up to the nearest size carb.

You will see a lean condition everytime with a built motor. Now if the motor is bone stock then you will can get away with that formula.