93egSLEEPER

Motor size does not always determine ITB size. A "good" set of V8 heads flow far less CFM than a stock b series head @ .500 lift.

Example:

My chevelle has a set of edelbrock performer RPM heads w/ 69cc chambers. PNP from the factory they flow 210cfm @ .500 lift. My GSR head w/ mild hand port flows right at 275cfm @ .500 lift. You tell me which will require more air.

4piston

Just had a customer make huge power on the ported ultra on a K series. I was pretty shocked. Hopefully one of these days they let me post the graph DOH! Right now they are holding back until he races.

maRtyMar

ok yea my bad I meant 50-ish mm not 40 :-/. ok so what about throat size? you dont think that if as long as the itb isnt smaller than the throat size is that it's big enough?

m4xwellmurd3r

http://www.jenvey.co.uk/jenvey/throt...envey-dynamics

According to jenvey a 40mm bore would be suitable for approx 50hp per cylinder. So I can see a mild sbc running a 40mm if its only putting out 400ish hp. 50mm is good up to 80hp per cylinder.