Is a 1970 Chevelle SS 12 bolt rear end same width as 8.2 in a 70 GS455?

I think they are the same. Thanks George

 

Yes, I have a 12 bolt chevy rear from a 1969 Chevelle in my 1970 Buick GS

 

Only major difference is the 12 bolt takes the bigger 1350 ujoint. Spicer makes an adapter joint to convert the 1310.

 

All the factory 12bolts I've had use the 1310 the 8.2 used the 3R joint

Some 12bolts used the 1330 joint

 

I believe it’s actually 3/4 narrower. We did a swap on my sons 70 to a Chevrolet 12 bolt from a factory 8.2

 

I have one in my 69 Skylark, all the brake parts switched over, everything aligned correctly except the driver side upper control arm rear seemed shorter or hole closer to the differential housing. But it works great

 

Thanks for help on this!