[AG]

Originally Posted by b-man

Had my ‘71-‘72 Buick/Olds corporate 8.5 10-bolt built by Monzaz and shipped to me in CA. It was built with a 30-spline Eaton posi and Moser axles along with 3.42 gears, something along those lines would be more than up to the task for a 400 Tri-Power 4-speed street GTO.

The nice things about that particular rear are the tapered axle bearings that are lubed with gear oil and the lack of C-clip axle retention like most other 8.5 corporate rears as well as 12-bolt rears. No need for the C-clip eliminator kits needed on 12-bolt rears that are known leakers.

The axles bolt in like on the much weaker 8.2 rears that have the failure-prone sealed axle bearings.

The 8.5 rears all have nodular iron housings which are far superior in strength to the grey iron 8.2 rear. There are nodular 8.2 rears but they’re quite rare and inferior to the 8.5 which uses the same robust pinion bearings as a 12-bolt, the lack of pinion support is why it’s not really worth investing in building a performance 8.2 rear.

The corporate 8.5 rivals the strength of a 12-bolt, they can take a beating.

I run a 1971 Nova 8.5" rear in my racecar with tubes welded to the center section, Strange spool, Moser 33 spline axles, Strange billet bearing caps and an LPW cover and it has held up flawlessly with 700 Hp. I've checked the guts several times and everything is good. A properly built 1971-1972 A-body 8.5" rear will more than adequate for any mild to wild street car, the ales are very beefy.