I was just wondering if a 10 bolt out of a 1971 cutlass will fit in a 1978 or do you need minor modifications?

 

It has been done, but the older axle is wider and the control arms will bind a little. The best thing is to either have it narrowed or cut it down yourself if you have the skills, or just get an aftermarket rear for it.

 

As Randy correctly points out, the upper control arm attachment points are at a different angle on the 64-72 axles. They will bind if you force them into place. Southside Machine used to sell arms with metal ball joints to fix this problem, but you're still stuck with an axle that's about 4" too wide.

 

If you want a better rear to swap in, look for a Grand National or 442 rear out of a 82-88 G Body. I think they are a straight bolt on

 

Actually, only the 84 H/O and 85-87 442 and GN. Expect to pay stupid money if you ever find one for sale. It's actually cheaper to buy a brand new 12-bolt custom built for a G-body than to buy one of these 8.5" factory axles.

 

Ok cause I'm selling one and somebody asked me if it would fit in a 1978 but I didn't think so but I wanted to make sure. Thanks

 

I sent you a PM. I may be interested in yours depending on the gear ratio