If you go with a T-5, be sure to get the "World Class" T-5 commonly found in the 5.0 Mustang. Two reasons why:

1) It's way stronger than the standard T-5
2) The gear ratios are better. The Mustang with the four cylinder turbo would not be advisable because the very short first and second gear.

But you still have a ton of fabrication to do. Does Quicktime make a conversion bell housing?