a833 with 904 yoke??

The 4 speed I got was build 10/66 and I was surprised that the yolk from a 1967 /6 auto fit on it. Would this make the trans weaker? I guess it came out from behind a 273. Could this type of trans also be from a 383 car with the small yolk? It is definitely a abody a833 mopar trans. What code(s) would identify what engine came in front of it.