I just found out my 65 corsa has a 66 saginaw trans (4-spd) and transaxle. Is it wise to leave the 66 trans and axle in? are there any advantages over the 65? What are the distinguishing signs to tell exactly what I have and what I am looking for. It is a 6 bolt trans/tranaxle connection I have. My fist clue I was working with the wrong thing was my gaskets didn't match in the rebuild kit. Thanks Rich Taylor