Chevelle rearend interchange
 

I am wondering what rears will fit in 68-72 chevelles. I have an 8.2 and want to change to 8.5. How about the big montes through 77?
Thanks

chevelles,cutlass, skylark, gto,lemans,are the same in thoughs years. I just did one!!!!! also went from 10bolt to 12 bolt on a gto....David.

Any of the GM A Bodies will bolt in...at least I believe they will. The 64-67 chevelle rearends will bolt in but they are narrower(I think 3 inches.. 1.5 per side)These 12 bolts are the best ones to find in my opinion but they are not very easy to find...( not in a junkyard anyway) Pretty easy to spot without a tape measure, just by looking at the distance from the shock mount to backing plate.Some of the 67's had the wider rearend...I think they changed midway through the year.I say this because I have a 12 bolt that came out of a 67 elcamino 396 that my dad had that I know for a fact had never been screwed with and to my surprise it was a wide one..not the narrow.

One warning if searching junkyards...GM did make a rearend that had 12 bolts in the cover but only 10 bolts in the ring gear. I know cause I got screwed on one when I was in Highschool. I Thought I was buying a 12 bolt positraction and when I took it to have the gear changed they guy couldn't believe it...10 bolt carier but 12 bolts in the cover. Took 10 bolt axles too. I believe it came from an oldsmobile. Also easy to spot cause the cover is smooth and round like a 10 bolt..doesn't have the "rib" in it like the 12 bolts did.

http://www.oldsmobility.com/10bolt-tech.htm