rear

[premo]

I recently installed a LT1 from a 95 iroc Z28 in my 86 buick regal, what are my options for changing my stock non-posi rear, to a posi. the only g-body buick that had posi is the gn and i dont want to pay that much money for a rear end that i dont know if it was abused

 

[-83MONTESS-]

Probly the easiest one to find would be one out of a monte ss. Just remember 83-84s had the 3.42s and the 85-88s had the 3.73s and not all of them were posi either. Other than that I think the Hurst/Olds had a posi option but not sure on the 442s.

 

[Kris_84elky]

Any 7.5 rear end from a 78-87 G-body with a posi will bolt right under your car, doesn't have to come from a Buick. But if you do go with an 8.5 the drive shaft will need to be shortened unless you get that too. Or you could buy a posi carrier and swap it with yours but it has to be the same series carrier as yours to match the gear set.

 

[-83MONTESS-]

Are you going more for the posi or just the gear change?

 

[snotrocket71]

i could be really wrong, but isnt the monte ss rear a 7.625? thus making it marginally stronger? at least they came with 3.73's after 84. that would be an easy doable swap and again i may be wrong but wouldnt you not have to swap the driveshaft? an easy but not always accurate way to tell if its a posi rear by just looking is to see if it has the pos tag on one of the cover bolts.

 

[-83MONTESS-]

i could be really wrong, but isnt the monte ss rear a 7.625? thus making it marginally stronger? at least they came with 3.73's after 84. that would be an easy doable swap and again i may be wrong but wouldnt you not have to swap the driveshaft? an easy but not always accurate way to tell if its a posi rear by just looking is to see if it has the pos tag on one of the cover bolts.

Yea for 85-88 they were the 3.73 with the 7.625". The easiest and probly most accurate way to tell if its posi is to turn one of the wheels and find out which way the other turns.

 

[Conan-64]

i used a rear from an 87 Monte SS. Got posi and 3.73 gears. Thae swap is very easy and the rears can be had for around $200.

 

[snotrocket71]

i could be really wrong, but isnt the monte ss rear a 7.625? thus making it marginally stronger? at least they came with 3.73's after 84. that would be an easy doable swap and again i may be wrong but wouldnt you not have to swap the driveshaft? an easy but not always accurate way to tell if its a posi rear by just looking is to see if it has the pos tag on one of the cover bolts.

Yea for 85-88 they were the 3.73 with the 7.625". The easiest and probly most accurate way to tell if its posi is to turn one of the wheels and find out which way the other turns.

That'd be a definite way to determine it. on a side note, is the driveshaft the same between a 7.5 and a 7.625? i was contemplating a cheap gear upgrade with a monte rear considering the pricey nature of the 8.5 rears.

 

[-83MONTESS-]

i used a rear from an 87 Monte SS. Got posi and 3.73 gears. Thae swap is very easy and the rears can be had for around $200.

I got a rear from an 86 SS with the 3.73s for $100!

 

[-83MONTESS-]

i could be really wrong, but isnt the monte ss rear a 7.625? thus making it marginally stronger? at least they came with 3.73's after 84. that would be an easy doable swap and again i may be wrong but wouldnt you not have to swap the driveshaft? an easy but not always accurate way to tell if its a posi rear by just looking is to see if it has the pos tag on one of the cover bolts.

Yea for 85-88 they were the 3.73 with the 7.625". The easiest and probly most accurate way to tell if its posi is to turn one of the wheels and find out which way the other turns.

That'd be a definite way to determine it. on a side note, is the driveshaft the same between a 7.5 and a 7.625? i was contemplating a cheap gear upgrade with a monte rear considering the pricey nature of the 8.5 rears.

From what I know the 7.625 and the 7.5 will take the same driveshaft. I hope im right because im planning on doing my swap soon. Id really like to find a 12 bolt though but I dont have a grand to spend right now lol.