Woody, Still easiest thing to do is stay with the 235/261 motor vs. the 250. Although many have gone over to this more modern motor, now it's like starting from scratch. The 51 car bellhousing is really an odd ball, will only accept a 54 or earlier car trans. You can however swap in a truck bellhousing if you want to keep the early motor. With the 250 style, you'll need a motor mount kit, a trans mount(automatic or stick?) So first you need to decide if you are up to building a drive train from scratch or attempting to stay sorta stock with pieces that mostly are a bolt in. There are vendors that carry these motor mount kits, try Langdon's Stovebolt or Buffalo Ent.(ads run on inliners.org site) Best of luck.
