You'll prolly find more info on one of the S10 boards but Ive done this swap eons ago and can tell you this:
TH400 will require trans tunnel massaging (BFH!!).
TH350 will work with no problem other than poss shortening the drive shaft with a long shaft TH350.
TH700R4 is a bolt in as they come stock in S trucks but you'll have to deal with the TV cable.
HTH