Interchangability

The 8-3/4 is a close fit, almost exact. Worst case, weld spring perchs is it I think. The width difference is small.
The exhaust system should not be a big problem. At best a minor tweaking.

If the engine runs well and the tranny is fine, yes, it's a good deal, but your asking blind people to make a call for you.

If you purchased the car solely for resale, then the answer is HELL YA!