You can use the t-bird tranny in the 5.0, but you will need to use a different pilot bearing. Not sure what the part number is or what car it came out of, but I want to say a ford Ranger. I may be way off on that so do a search and you will find what pilot bearing you will need. As for strength the t-bird tranny is weaker than the 5.0 tranny so take it easy on her if you want it to last. I think they are only rated to 230 ft/lbs of torque.
Mario