I have a 1972 Mach 1 that has a 351C backed by a FMX Auto, and 275 open 9" rear end. Soon I am going to be replacing the tranny with a C-6, and new 350 gears.I need to know if i will need a different cross member and what i can take a drive shaft out of to fit my car

 

Depends on the tailshaft length you get, and if the driveshaft needs to be a different length, you can get it cut or a new one made at most machine shops. My Mach has the FMX still in it. A Grande I had a C4 bolted right in. That was a long time ago, and dont quite remember everything I did. Like almost 20 years.

 

why are you swapping out the FMX is it due to the weight or do you just like the C-6 better