1991 5.0 Automatic stang. i would like to know what size of throttle body i should get? i was looking at a 70mm or 75mm. i have bigger MAF, bigger cam 0-60mph is about 7.2 sec but do Quarter in about 14.4 102mph it pulls after 2500-will go up to 6500, 1.6 rockers, 3.55 gears, shift kit, intake...