Engine swap 2000 chevy impala to a 2003 Buick century

Hi Andy, I can't definitively answer your question however I can say I ran into major problems trying to swap an 01 Century engine and transmission into an 03 Century. Even though the engines and transmission appear to be the same there are differences that make at least the transmission totally incompatible. Hopefully someone else on here can provide more insight however I just didn't want someone else to have a costly mistake like I did.