I was the putting the transmission in a '73 Ford. The same technique should help with other makes + models.
Buy 4 bolts of the same diameter and pitch as the ones that hold the tranny.
The bolts you buy should be a few inches too long.
Cut the heads off.
Grind a ball end on each .
Thread them into the holes.
Bring the tranny into alignment on them. Push it into place.
Remove 1 "cutoff bolt" at a time, and put the real bolt in.