ORIGINAL: 90Mustangfan

you would get more throttle response with a 500, your right prolly more tq too....Now it says for a 302, youll need a 534, right off the bat youll need more car you alredy excceded the 500cfm carbs capibility w/ a mild H/C/I...what if you went more agressive. ie afrs,eldel,and rebuilding the motor boring it to a 308....also you forgot to consider that, some companys over rate their carbs...for examp. they say it will flow 600cfm, in reality it could flow as low as 580cfm, or it could flow more mabye 620cfm...every carb is different, every company is different...I personally would would leave room to upgrade by getting the 600, that way in the future you wont be buying another carb, cause you got to small to begin w/. say it you rebuild your motor from a 302 to a 308, afrs 165 ported and polished, edel intake, LT's,h-pipe, 1.7RR's, cam aprox .550 lift., that little 500cfm carb isnt going to be enough, better safe than sorry. think for the future, what if he wanted to go w/ a blower or turbo..? how well will a 500 cfm be then... its easier to relate like this its the same for Throttle bodys. if you have a stock car 70mm is too big, you will kill throttle response and lowend tq., but when you mod and do a mild H/C/I, 70mm is perfect. and then if you add a blower and more agressive build then 70mm will work, but then 75mm would be better. see what im saying, you prolly know more about carbs than I do, but its better safe than sorry, i would want to buy 2 carb when you can just buy 1...