carmine34

I'm put a 351 Cleveland in my 70 Mach 1. The 351C motor and C4 trans are from a 72 Montego and for some reason the standard 1969 driveshaft 51" between yokes is too long for my car which has a 9" rear with 3.00 gears open. They fit nicely and the tranny fit fine with the standard crossmember and rubber mount. Did some bigger cars have a longer tailshaft on their c4s?. I found what I think is an FMX driveshaft that has a distance of 50" between yokes so I'm going to just swap the yoke and it should be perfect. But what I want to know is; are there different length C4s?. Is this an HD c4? Thanks

03gt04mach1

Some Tail Shaft Splines on the rear of C-4s tranny have different teeth counts. Make sure the yoke matches and slides in. Not sure if you have a HD C-4. If the Montego came with a V8 engine, probably. But, if it had a straight 6, you may have to beef the tranny up, with larger clutch packs and internals.

carmine34

Yes the 351C Motor and C4 trans are from the 72 Montego. Is it possible the 9" pig is bigger than a stock rear end? I thought the rear end was original but maybe not?

03gt04mach1

Yes, that would be hard to say, after all these years. You'd have to look for a build sheet to find out about the rear end. Not sure where you'd go for that....Maybe GOOGLE it?