Ok I need help. There have been rumors that chevy put the 8.5 rear end in some of the 71 and 72 chevelles and maybe Monte's. How do you identify them from the 8.2 rear end?? is the back cover diffrent? bolt pattern diffrent?? castings on the center section itself, I know that the 8.5 in the firebird and camaro have small tabs on the bottom of the housing center section. Like i said i need help. thanks

The bolt pattern of the cover is slightly different.

Not very many 8.5 ten bolts were installed in 70 - 72 models. In fact, you'll have better luck locating a twelve bolt. But this is what you're looking for, just in case you do find one.

http://www.chevelles.com/showroom/data/500/medium/rears8_5and8_2.jpeg