G-Body rear ends

[see2xu]

I've been under the impression, for decades, that the hi-po G-Bodies from '82 on, like the Monte SS, Grand National, 442, and 2+2, all left the factory with the 8.5" rear end. But an '86 Monte SS just coughed up a 7.5" (open) 3.70.

No evidence the car's ever been altered.

Any insights?

 

[ck80]

Monte ss and 2+2 never got a 8.5 factory.

Just the buick turbo gbodies 1984-up, the 84 Hurst Olds, and the 85-87 442

Later monte ss got the 7.625 which is a teeny bit better than 7.5 but still only got 28 spline axles from the factory unlike its later/fbody cousins

 

[see2xu]

Monte ss and 2+2 never got a 8.5 factory.

Just the buick turbo gbodies 1984-up, the 84 Hurst Olds, and the 85-87 442

Later monte ss got the 7.625 which is a teeny bit better than 7.5 but still only got 28 spline axles from the factory unlike its later/fbody cousins

Thanks!

 

[64nailhead]

Sounds like you’re in need of something beefier than the factory 7.5. If that’s the case, then come up with a budget. If your budget for rear, center section, brakes. And depending on your budget, an aftermarket bolt in unit start looking like a better deal.

The ‘might as wells’ can add up in a hurry.

 

[PBGBodyFan]

Monte ss and 2+2 never got a 8.5 factory.

Just the buick turbo gbodies 1984-up, the 84 Hurst Olds, and the 85-87 442

Later monte ss got the 7.625 which is a teeny bit better than 7.5 but still only got 28 spline axles from the factory unlike its later/fbody cousins

It’s even worse for the 7.5/7.625”, they were 26 spline axles.

 

[Built6spdMCSS]

Yea the Gbody was 26 spline, even the 90s S10's got 28 spline.

 

[doood]

It's quite irritating that there isn't an aftermarket bolt-in GM rear for under $3500. You might be able to get a bolt-in Ford 9 for $2200. Also, while it might 'bolt in', will the instant center be in the right place? Are you going to take their word on it? Sounds like the numbers of 8.5" g-body axels ever made is on the order of 30,000 units - they're rare now.

 

[Built6spdMCSS]

Yup might get lucky finding the Gbody 8.5 and build it up for power, even then the people who have them try to price them to Willie Nelson standards.

I went with a QP Custom 9" Housing at the time I did mine because I had a 9" in my Camaro. Sold that Fbody Housing to a buddy when the Camaro wrecked, bought the Gbody Housing, cut down the Axles and put it all back together.
Can't go any less with the power I'm making and a manual, I'll beat the crap out of an 8.5 over time and need to rebuild it.

 

[86LK]

I spot them every once in a while for sale, and the usual price seems to be about $1500 for a piece that looks like it was pulled from a junkyard and hasn't been touched in over 20 yrs, let alone rebuilt

there are other options, it just depends on your intended usage, budget, and your ability to build one

 

[scoti]

Things valued @ $300-500 years ago when they were more readily available are going to be around $1k or more now simply because of supply & demand + inflation of the dollar.

It's the same standard as the cars themselves these days.