Rear End

SOME/many 7.25SGs have done pretty good behind teeners,automatics,stock rear suspensions and street tires.If you want to try it, pop the cover and check the cross-pin to case fit. If its tight, a fresh load of oil, and have a go. If I could I would try to decrease the side gear backlash.
But an 8.25 SG should take anything your teener can dish out. At least until you stroke it.They're cheap and plentiful, and well-supported as to parts.