Someone correct me if wrong but the 70 and up rears are stronger but they are longer in the snout by 1" and you have to shorten the driveshaft, I believe there is info here if you look up your year. The 10 bolt 8.2 is really only good for about 350hp depending on how hard you're going to dump the clutch, the latter 8.5 is better but if you're to beat the hell out of it Currie makes a bolt in 9"