what size throttle body?

[1991vert]

well this is my plan. i'm buying a cobra upper/lower intake, getting 1.72rr, 76mm c&l MAF, and a 65mm throttle body. i also plan on getting some thumper heads next winter along with a cam. to save myself the trouble/money should i get a 70mm? or would that be too big without the ported heads? or will i be just fine with a 65mm?

 

[Michael Yount]

You're no where close to benefitting from the extra size of the 70 - there'd be no performance gain over the 65 even with the addition of the heads and cam.