The 283, (which you probably know came in the '57) or any smallblock with the four mount holes on the front of the block, would bolt in. There are small "L-brackets" that bolt to the front, and they sit on studs and round cushions coming up from the front crossmember. You might find a restoration supplier with mount kits.

I would suggest you use the search engines, like
google, to find a custom transmission crossmember to replace the rear bellhousing mounts used on the original car.