82s15

I just recently purchased an 82 s15 gypsy edition roller and it was setup for a 327. I want to put a 1996 350 vortec or a 2003 5.3 in it and a t5. I’m having a hard time trying to find a t5 out of a 90s s10 but i can easily find t5s out of 90s mustangs. I was wondering what would it take to use a mustang trans in this truck. Any other tips and tricks are greatly appreciated as well.