Borg-Warner T-50 came in H-bodies. Not sure of any direct swaps but the H-body crossmembers can be modified easily. I took a early Saginaw crossmember and had the center cut out of it and moved back an inch or so to fit the swapped in T-50 on my first '72 Vega. Shop only charged me like $20........
-The S-10 T-5 rear case that holds the shifter is the best suited for an H-body, so I've been told. This rights the shifter back to level as the F-body T-5s clock the shifter at an angle(towards the passenger side, I think).
-The V8 versionhas better ratios than the V6 version. 0.65:1 overdrive versus 0.8x:1.
-The early models have a gear drive speedo pickup.... the later models have an electronic speedo pickup and the adapter is a few hundred dollars(cut off years is around '87)........
-Torque arm mount is different.
There are a few here and at Bob's site that have done this swap. Should have lots of help on this one.
Here's a couple sites with some helpful tips and photos Bill Barnhart sent me some time back:
http://www.inliners.org/Jack/T5tech.html
http://www.inliners.org/Jack/t5_page.html