HELP HELP HELP!! Need to Id this BOP rear end.

565bbchevy

Geezer
Aug 8, 2011
8,647
113
Michigan
He did mention that the rear was wider, but he compensated by using rims with a wider backspace...besides using the aftermarket upper control arms.
I do believe pontiacgp said he bought different rims in the rear to fit the 8.2" and I think it was some off brand conversion arms that are no longer available that he used.
Changing rims can be a costly adventure and if you love the ones you have there is a good chance there will not be rears available with enough positive offset to fit or maybe your rims are discontinued so then you are buying a whole new set if you want them to match.
Sometimes the money you save on something costs you more in the long run when you have to make it fit.
 
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Jas

n00b
Apr 10, 2021
4
1
Okay Guys I need some damn help. For 100$ I couldnt resist buying the rear end I found online. We all know above 400 HP the 7,5 is going to explode at some point if you arent careful and smart. That being said I found this 10 bolt B.O.P. rear end. The rear end was in a 1971 Lemans( this is what is making this hard as hell). 1970-1971 was the year GM decided multiple axles from all its divisions was no longer the way to go, so SOME of the 1971 vehicles got the 8.s other the 8.2. The Lemans is one of only a few vehicles that had both and a very rare Nodular rear end.

So to the point....I need help determining for sure what the hell I have? Either way its going in my 87 Aero . I have done all the research, and know about pretty much all the different ways to identify them but with so many variations and possible random rears ends I need some help. I have measured the cover bolts which should be 3 3/4 . Pinion nut, Spider gear bolts...and guess what ...they all dont align!! I will post every identifying mark and picture I possibly can. I took the cover off and the only thing I havent done is pull it totally apart and measure the diff. So I BEG of you someone tell me or help me at least narrow it down. I do know it was the original axle out of the 1971 Lemans , Has the bolt in axles and has tabs that hang down on the bototm of the diff. So here we go. View attachment 172684 View attachment 172685 View attachment 172686 View attachment 172687 View attachment 172688
 

Jas

n00b
Apr 10, 2021
4
1
Okay Guys I need some damn help. For 100$ I couldnt resist buying the rear end I found online. We all know above 400 HP the 7,5 is going to explode at some point if you arent careful and smart. That being said I found this 10 bolt B.O.P. rear end. The rear end was in a 1971 Lemans( this is what is making this hard as hell). 1970-1971 was the year GM decided multiple axles from all its divisions was no longer the way to go, so SOME of the 1971 vehicles got the 8.s other the 8.2. The Lemans is one of only a few vehicles that had both and a very rare Nodular rear end.

So to the point....I need help determining for sure what the hell I have? Either way its going in my 87 Aero . I have done all the research, and know about pretty much all the different ways to identify them but with so many variations and possible random rears ends I need some help. I have measured the cover bolts which should be 3 3/4 . Pinion nut, Spider gear bolts...and guess what ...they all dont align!! I will post every identifying mark and picture I possibly can. I took the cover off and the only thing I havent done is pull it totally apart and measure the diff. So I BEG of you someone tell me or help me at least narrow it down. I do know it was the original axle out of the 1971 Lemans , Has the bolt in axles and has tabs that hang down on the bototm of the diff. So here we go. View attachment 172684 View attachment 172685 View attachment 172686 View attachment 172687 View attachment 172688
Ran one with alburn Limited Slip 4.11 gears in a 1987 SS MONTE at Crossville Tn strip for 6 years , 1/8 , 6.48-7.01 depending on tires and weather and still driving it every day , but I guess it depends on hp and drivers , there stronger than you think. If I still raced maybe it would be trashed I don't know but I still street race and its still going. My plans were to run her untill it went and go 9" ford , maybe she heard me say ford. James
 

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