8.5" in '84 Cutlass Supreme?

[tc1959]

I agree with Stones on this one here..........Think about ot for a second. The only G Body cars that the General put the 8.5 rear ends in were the high performance muscle cars.....YOu know the HUrst Olds, Grand National, T-Type and the 442....That being said, lets look at the rest of our G-Body cars......They were turtles from the factory and the 7.5 rears were adequate....Apparently the General forgot that these cars would be modified through the years....I think they shoulda put the 8.5 rears in all our G-Body cars in the first place. Anyways, when I decided to build my Monte up the first thing I did was replace the stock 7.5 rear with a '69 Chevelle 12 bolt 8)

That's a cool Idea. I always thought the older Chevelles were wider than a G-body.

 

[JBreu]

I agree with Stones on this one here..........Think about ot for a second. The only G Body cars that the General put the 8.5 rear ends in were the high performance muscle cars.....YOu know the HUrst Olds, Grand National, T-Type and the 442....That being said, lets look at the rest of our G-Body cars......They were turtles from the factory and the 7.5 rears were adequate....Apparently the General forgot that these cars would be modified through the years....I think they shoulda put the 8.5 rears in all our G-Body cars in the first place. Anyways, when I decided to build my Monte up the first thing I did was replace the stock 7.5 rear with a '69 Chevelle 12 bolt 8)

That's a cool Idea. I always thought the older Chevelles were wider than a G-body.

The 78-88 G Body rears housings measures 52.125"
The 64-65 Chevelle 54.250"
The 68-72 Chevelle 55.250"
For the three inches that my rear is , isn't that much of an issue to even worry about. Some people have "hidden" the extra width with backspacing on their wheels......

 

[supercrackerbox]

I always wondered why GM put 7.5 rear ends in all the 90s F-Bodys ? Some of them where pretty good runners.

Some of them were. And they still used the 7.5" rears all the way through the end of the Fourth Gen too. A buddy of mine has a '99 Z-28. The ONLY mod done under the hood is headers. The LS1 has been rebuilt, but is otherwise stock. But he also runs slicks and a trans brake. He's destroyed three rears so far, and the fourth is making some nasty noises.

 

[88hurstolds]

If you do the math it's cheaper to buy a Ford 9" for a G-body than it is to find an 8.5" and have to rebuild it.
Most people just slap in the 8.5" not caring that most likely it has close or over 100k miles on it and that posi is NOT gonna hold up under any race conditions. In the long run that 8.5" with all those miles is no better than having a nicely rebuilt 7.5"
Think about it, most don't and just slap in the rear after whoring a good numbers matching low production rarity.

Ford 9" for those who are serious, GM 8.5" without a rebuild if you just want 'braging rights'... because that's all it's good for until your first bracket race... I just spoke with a racer yesterday about this and he was bent out of shape over how people charge high dollars for something that is no better than putting the money into something that will actually hold up like a 9".

 

[Chris Van]

I probably had $1000 or so "total" in my 8.5 that I bracket raced for years. I probalby have about $3500 in the 9 inch that I just put in last winter. So once again, it all depends on just how much you expect from your rear.

 

[mheath717]

Wow... So that 8.5 sitting under my parts car Hurst might be worth keeping. I had no idea that they were worth that much. I almost sold it a month ago for $150. I just decided to keep it in case something happend to mine. 😀

 

[JBreu]

Wow... So that 8.5 sitting under my parts car Hurst might be worth keeping. I had no idea that they were worth that much. I almost sold it a month ago for $150. I just decided to keep it in case something happend to mine. 😀

Yeah that's a keeper..Don't sell it unless you really need the cash..........BUt I'd give you $151.00 for it 😀

 

[Chris Van]

I sold my 8.5 for $1000.00
It did have a spool, c-clip eliminators and Moser axles in it though.
Originally, I traded a pitcher of beer for it and I did the work to swap it out with a stock 7.5

 

[stomis]

If you do the math it's cheaper to buy a Ford 9" for a G-body than it is to find an 8.5" and have to rebuild it.
Most people just slap in the 8.5" not caring that most likely it has close or over 100k miles on it and that posi is NOT gonna hold up under any race conditions. In the long run that 8.5" with all those miles is no better than having a nicely rebuilt 7.5"
Think about it, most don't and just slap in the rear after whoring a good numbers matching low production rarity.

Ford 9" for those who are serious, GM 8.5" without a rebuild if you just want 'braging rights'... because that's all it's good for until your first bracket race... I just spoke with a racer yesterday about this and he was bent out of shape over how people charge high dollars for something that is no better than putting the money into something that will actually hold up like a 9".

I'd rather have a 100k mile 8.5 than a fresh 7.5 any day of the week. You cant freshen up inadequate design with a rebuild...

That being said, noone is gonna argue that the 9" is superior to the 8.5in 10 bolt. But I will openly argue that people that try to say that they cant hold up to power are on crack. Just look at the loads of videos of typhoons, cyclones, GNs, 2nd gen f-bodys, and our cars wheel standing and running in the 10s with the 8.5....

That being said my car came with an 8.5in. And if I blow it it will get rebuilt with yukon 4.10s, mosier shafts, and a freshened posi. But its highly unlikely it'll go.

I'm sorry but your cost argument is bogus unless your talking about someone like myself thats gonna get a $100 junkyard 9in and do the brackets themself.

 

[19cutlass79]

If you do the math it's cheaper to buy a Ford 9" for a G-body than it is to find an 8.5" and have to rebuild it.
Most people just slap in the 8.5" not caring that most likely it has close or over 100k miles on it and that posi is NOT gonna hold up under any race conditions. In the long run that 8.5" with all those miles is no better than having a nicely rebuilt 7.5"
Think about it, most don't and just slap in the rear after whoring a good numbers matching low production rarity.

Ford 9" for those who are serious, GM 8.5" without a rebuild if you just want 'braging rights'... because that's all it's good for until your first bracket race... I just spoke with a racer yesterday about this and he was bent out of shape over how people charge high dollars for something that is no better than putting the money into something that will actually hold up like a 9".

Debates like these always makes me smile 😀 This conversation is all point of view, sure it might be cheaper to go with a new 9" that's set up for g-body (you must be making new comparisons because your not going to rip any rear from a stock ford that will fit in a gbody), because if your talking used parts to used parts and the guy cannot rebuild his own rear end 7.5" or 8.5" then most likely he may not have the "know how" to modify his used 9" so he still has to pay someone to do it for him, so it makes it kind of moot point. If we are talking all about price point (cheaper this, cheaper that) the cheapest way is to learn how to do it your self. When I swapped in my 8.5 gn rear I got for $300, all it cost me to rebuild was the cost of the bearing and seals and gear oil.

But to each his own! 😀
wade