Help motor swap

Yes, you can bolt a 66 slant tranny to any 66 slant engine (170 or 225), if that is your question. You should explain exactly what you are trying to do, and we can help more. Certain combinations can easily be made to work. The main issue is mating the torque converter snout to the register hole in the crankshaft. In 1967, both snout and hole became larger. You can get an adapter ring to fit an early snout in a later engine (must be tight), but not vice-versa. The flexplate bolt hole circle also changed, but an easy swap and many after-market flexplates have both bolt hole circles.