Trying to figure out which centerforce dual friction clutch to get. Will be going in a 68 Dart, 340, 9.5:1, x-heads, ld340, leaning towards comp cam xe268, 750 carb, 833, 3.55 gear. I see they list two, # 269675 about $400, and 269739 about $467. Not looking to go racing, just street fun...