The 360 is a small block and the only different items on a 360 that would slow down a swap wold be the oil pan, a truck pan has a rear sump, you need a center sump.
All small blocks are the same dimentions externaly minus the different exhaust manifolds.
A 727 holds more power but also uses more power to run.
A 904 is capable of high horse power if built right, which leads me to say, make sure the tranny, which ever one you use, is built well.