i was wondering, because i'm possibly buying a 5.0 thunderbird(86, its for the engine, 500ish if i buy it) it comes with a posi rear end, so i was hoping i could use the rear end on my 66 mustang, i'm doing a 5.0 t-5 conversion on it. So i thought, hey score a rear end along with an engine...can anyone help me out here?

 

Your 66 mustang has leaf springs and the thunderbird has coil springs with upper and lower control arms. I assume it's a turbo coupe since the 8.8 you speak of is limited slip?. My point is that the 8.8 won't have spring pads but WILL have a bunch of stuff you don't need. If it's a out of a turbo coupe it may (not sure) also have rear disc brakes.

You'll have to consider the work involved, added parts you'll have to buy to get this rear to work etc. (A custom driveshaft will be a given either way) If the rear in your 66 is a nine inch, you'd be better off putting a limited slip unit in it and forgetting about the 8.8 conversion IMO.

 

you said 5.0 thunderbird, so probaqbly no rear discs.