trans swaps..

Sorry I don't know what your 3 spd. is called. Never had any dealings with 3 speeds. The 4 speeds are called a A-833. All autos since somewhere around 1960 are called Torqueflites. There are 2 versions. The little one (the 904) and the bigger one (the 727). The one behind your 360 is most likely a 727 since that's what came behind about 95% of 360's but there's no guarantee. It could be a 904. You would have to identify it by the shape of the pan. If the pans basically square it's the 904. If it's square with a "kickout" on the passenger side it's the 727. 4 speeds can be found in the for sale section on this board, on e-bay, on other boards, in junkyards, at swapmeats, etc. Just remember if you do switch to a 4 speed you'll need a 360 specific flywheel. Their balanced different than all other small blocks and their pretty rare.