http://www.oldsmobility.com/10bolt-tech.htm This link has excellent info and pictures about our rears 65-72 and others, also good info on posi-units---if someone posted it before apologies :spank: for a rerun---Pete
The Oldsmobility 10 bolt link is often put up, usually when one is trying to show the difference between some form of 8.2 and 8.5 10 bolt rear. Be advised, this link is chocked FULL of errors and omissions :3gears: Roger
Pete Roger is the resident rear end meister. No need to look it up-- just post for Roger to show and tell.
Got it Jim--I got my posi last week and new gears 3:42 which I like--the rear end shop thought I had an 8.2(in my 72/455)--I told them it was 8.5 (from you guys info) and then they realized that an 8.2 wasnt right :af: (when they tried to put it in)---they were very apologetic but they had it done in about 3.5 hours :grin: Pete
This website lists two different type covers for the 8.5 10 bolt. Any difference other than the cover between the two rear ends? 11" Oval Cover - 10 Holes Bottom: 10 5/8" Irregular Cover - 10 Holes
There are at least 4 different shaped rear covers used by GM over the years on the 8.5 10 bolt r/e. One of the lastest being the exotic GNX rear cover. Good reason to never judge a rear by it's cover. Other differences... of the 3 different '71-72 8.5 A-body housings, the most common takes the scallop sided cover. The 2 less common '71-72 8.5 A-body hsg's take the round style cover. Due to the way these hsgs were cast, the covers cannot be interchanged between scalloped & round, at least without some creative gasket work. :3gears: Roger