If the TH350 was offered on 85 and earlier Blazers why would swapping a TH700R4 for a TH350 be very hard? if i found a trans out of an older Blazer it should be a snap. Besides you can't tow with 700R4 in 4th gear.( owners manuel says not to.) And you can't put a very big cam in and make it lug in 4th.that's why i want a 350.