1996 olds sierra to 1999 century engine swap

[ghalacsy]

My father has a '96 olds sierra with the 3.1L v6 and a 99 century with the same engine. Other than a motor mount location difference, throttle body and different intake manifolds, what else should I be concerned about having to swap them. We would be moving the engine into the 99 Century as it has the better body. Is there a difference in the transmissions? Any help would be helpful.

Guy