This Super Stock pulling truck (6200lbs) runs a 530cid rated at 900hp or a little more I think, and he runs the NP435 4th gear (1:1) dual disc clutch with a Profab reverser (choose your gearset) transfer case and rockwell 1 speed rear end, and has been running if for 15-18yrs and hasn't broken it yet! I think that's amazing..!