This posi unit was purchased by me from Todd(BADDABUICK) about a month ago.I bought and I believe he sold in good faith---advertising it as belonging to a 71 SKYLARK. My rear end guy says it does NOT fit my 72 GS 455 10 bolt carrier about 1/2" OFF---my rear guy claims it goes to a Chevy. From the numbers in the pic can someone tell me and Todd who is RIGHT?My car is a number match--engine and tranny wise so I doubt if my rear has been changed but I can't PROVE this. I will ABIDE by whatever the board has a consensus on--- Sincerely Pete Gross
that is an 8.5 10 bolt posi 3 series used in gm 8.5 10 bolt from about 71 up.it should work for chevys buicks etc.if it wont work then you have a 8.2 10 bolt which is the older style from 65-71......
Yep, thats definately a 71 up 8.5 found in camaro's, trans ams, buick wagons etc. If its the correct 72 rear....... it fits
Pete, The carrier pictured above is def a low (2.73-5.57) "Corporate" 8.5 clutch type posi carrier used by GM from the mid '70's up through early '88. Though it will have recesses in the side gears for c-clip useage, it will work fine in a bolt-in axle 8.5 application. Personally, have propperly rebuilt hundreds of that particular carrier, & used them in '71-72, & 73+ bolt-in axle r/e builds, they work decently until one really starts popping them hard on slicks at the track in a relatively strong car. Usually in an auto trans 3700-3800lb A-body, one can get down into low 1.60 60 foot times before the oem carrier design is a weak point. Before this point, the 28 spline axles are a liability, thus why I upgrade so many 8.5's with new HD Eaton carriers & 30 spline Moser axles p Further posi identification... Original early low ratio corporate 8.5 posi carriers did not have the large #8's cast on the ends, just the small numbering 41048. Also, all the oem '71 useage 8.5 posi carriers I've removed were of the Warner-Motive cone design... no large open windows & "S" shaped preload spring, & near worthless when worn out. A few Warner-Motives slipped into '72 models, though by '72 vast majority with a factory posi carried an "S" spring "Corporate" 8.5 clutch type posi. Good luck on your build. :3gears: Roger
Roger,thanks for the help---Todd is correct in what he sold me and that is much appreciated. My problem is MY rear-- is it an 8.5? Can you tell from the pic I have posted? Thanks for any help Pete
Pete, Your A-body rear is def a 71-72 8.5, as you've noted, prob the original to your car. The center housing is the most common version with the big protrusions @ 5 & 7 o'clock, pan has two "cutouts" & there are two plugweld holes per axle tube (visible as in your pic). The less common version of '71-72 8.5 center housing does not have the big protrusions, also from the rear view of the centerhousing, will only has one plug weld hole per axle tube, not two. Good luck on you build, Roger
