Hi guys. My 73 Catalina has a 400 motor with 2bbl and th375 trans. The th375 won’t shift out of 1st. From my understanding it’s nearly identical on the inside and outside to a th400 but uses a th350 tail shaft , 27 spline output shaft instead of 32, and a different yoke (th350)? If I buy a BOP TH400 can I just pull the tail shaft of my th375 and put it on the th400 for a direct replacement? Thanks for the help 

Easiest thing to do is get the yoke with the turbo 400...Then change the U joint and the old yoke from the drive shaft...If the trans missions are same overall length...The drive shaft will work without having to alter it....