I use a slightly different method of calculating CFM- - - - -since it takes two turns of the engine to get a 4 stroke cycle on all the cylinders, I plug in cubic inch displacement times 1/2 the desired RPM- - - -which gives "cubic inches per minute". Divide by 1728 (cubic inches in a cubic foot) to get "theoretical" CFM. For a more realistic guesstimate, use 90% of that number to account for less-than-complete cylinder scavenging on the exhaust stroke.

Example- - - - -
350 cubic inch Chevy V8
6K RPM

350 X 3000 = 1,050,000 cubic inches per minute, or 608 CFM theoretical volume

608 X 0.9 = 547 CFM- - - - -now- - - -why does somebody need a 750 CFM carburetor (or bigger) on that engine?

Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!