73CSS,
The 8.5" rear is a good rear. David Henninger runs 9.2's in the Hot Rod Real Street class with one(N2O on a Buick V6). He ran the same rear when he was running mid 8's in Super Street. He uses 35-spline axles, spool, c-clip eliminators, and welded axle tubes.
As good as the rear is, you are going to have to modify it to get it to live behind your combo. There are quite a few aftermarket parts available. At minimum I would suggest aftermarket alloy axles. You will probably be safe with the factory spline count.
Good Luck,
Jason Gore
AKA DragRacer
[email protected]