78 Olds Cutlass rear end

[Carsten]

Hello ! I need some informations :
Are ther any other cars that use the same rear end which is in my 78 Oldsmobile Cutlass Supreme?? Is it the same as in a Malibu or El Camino or ?? Maybe Astro or so ??
i am looking for a second rearend for my car , with a higher gear ratio and maybe one that could take more horsepower because the engine is a 350 with about 400 Hp`s and i will take it on the strip this year with slicks.
Are ther any rear end changes possible ??
Thank you for any help and information , because it is somehow complicated to find informations and parts over here !!
Carsten

 

[KrisW]

Most 78-87 G and A body rear drive cars will interchange; this is your Buick Century and Regal, Pontiac Grand Am and Grand Prix, Chevy Monte Carlo and Malibu, and of course other Olds Cutlass models.

This is the easy part; the hard part is that most of these cars have the same weak 7.5" 10 bolt rear. There are some Monte SS and Buick Grand Nationals that got the stronger 8.5" 10 bolt rear, but these are very hard to find and expensive. To look for these, your best bet is eBay, and then to pay shipping to Germany.

Another option; buy an aftermarket rear. For overseas guys, the cheapest and best way to go is to buy the aftermarket Ford 9" rear end housing and have it shipped to you. Then buy the axles and third member (with the gear ratio of your choice) from eBay. Most companies that make the aftermarket 9" housing make it to re-use your original brakes, too. Try Strange and Moser in the USA for these housings.

Good luck, man!!

--Kris

 

[Carsten]

Rear end

Most 78-87 G and A body rear drive cars will interchange; this is your Buick Century and Regal, Pontiac Grand Am and Grand Prix, Chevy Monte Carlo and Malibu, and of course other Olds Cutlass models.

This is the easy part; the hard part is that most of these cars have the same weak 7.5" 10 bolt rear. There are some Monte SS and Buick Grand Nationals that got the stronger 8.5" 10 bolt rear, but these are very hard to find and expensive. To look for these, your best bet is eBay, and then to pay shipping to Germany.

Another option; buy an aftermarket rear. For overseas guys, the cheapest and best way to go is to buy the aftermarket Ford 9" rear end housing and have it shipped to you. Then buy the axles and third member (with the gear ratio of your choice) from eBay. Most companies that make the aftermarket 9" housing make it to re-use your original brakes, too. Try Strange and Moser in the USA for these housings.

Good luck, man!!

--Kris

Are this 8.5" 10 bolt rear ends in any other cars of GM ?? So i can search over here??
Thanks for that , Carsten

 

[KrisW]

8.5 10 bolts were put in tons of GM cars from the 70's and 80's, and even some pickup trucks. The problem is that only the G-body and a-body cars I listed above will fit your car. The mounts are cast iron, so you can't just cut them and weld them on in a different position.

The bottom line is that you aren't going to find a proper rear end for your car anywhere in Europe; you will have to have it shipped in from the US and then pay the outrageous taxes that Europe demands to put it into your car.

Sorry.

My wife is Bulgarian and I am dealing with similar issues getting stuff to our place in BG as well; there just is no easy way to do it. Scratch that, there is no cheap way to do it; it is easy enough to pay the money. The catch is that you must have the money to give to the government for your privilege of importing old car parts.

 

[Blake442]

A 7.5" will not last long behind 400+hp and slicks, and it's not worth the gamble.

As far as a direct replacement goes, the 8.5" is your best bet, though they are expensive.

They came in '84 Hurst/Olds', '85-'87 442's, and '84-'87 turbo Buicks ONLY.
No Monte SS's or Pontiacs ever recieved 8.5's.

On the plus side, between '86-'87, they built over 35,000 Turbo Buicks, so they are out there, you just have to be willing to put up the money for it.

Like Kris mentioned, your best bet is an aftermarket Ford 9 inch.

 

[Carsten]

Rear end

seems to be a little difficult to find something over here... So i think i will make the car a little lighter... Has no air condition..no heater...no carpet.. no rear seats and will get some light sport seats ! Will test what happens ;-) ! So i will start looking what kind of rear axle will be ( Ford ) good and not to expensive...
Thanks for your help !!
Carsten

 

[shotgun]

I will most likely get shot for this but, I your case building a stouter 7.5 may be an option.

I am all for building for strength, my Wagon has an 8.5, Cutlass has a 12 bolt but sometimes it is not feasible.

A "built" 7.5 recipe is:

7.625 Posi and gear set from a Fbody, set to almost zero lash
Aftermarket axles
Aluminum cover that preloads the bearing caps
Semi synthetic fluid

There is even a tubular brace kit that attaches to the rear cover. I never used one so can't say either way.

Shipping on the axles/cover should not be as killer as a whole rear.

I have seen guys get into the 10z on a with 7.5 but I cringe everytime they launch.

It may last a long time if you only hit the tracks every now and then with slicks. On street tires you will loose traction before loading the rear.

If you bracket race weekly, it is a matter when, not if, it will blow.

If you put the car on a diet, it will be loaded/stressed even less.

Good luck either way

 

[Carsten]

7.625 Posi and gear set from a Fbody

Sorry , what are F bodies ?? And what does that exactly mean? I am very new in The whole thing , did dragracing the last 10 years with a bug ;-)
Thanks Carsten

 

[shotgun]

F-body = Camaro/Firebird


Back in the day, I used to run a 56 Oval, 1776 motor, Webber Bug Sprayer carb, aluminum flywheel,009 dist, "Blue" coil, custom extarctor etc etc with the original transmission.

Nothing could touch it for the first 100 feet!

 

[Carsten]

oh.... ;-) mine is a 69 model built for the street and the strip with close ratio gearbox , weldracing front and back , lexan windows all around and had a 2332 engine in it with 48mm ida carbs msd and so on ! made over 220hp on the flywheel ! But now engine is sold and i woul like to play with the V8 stuff... Alle the people over here love mopars and old chevy`s... Not many people lik the g-bodys... I do not know why??
Greets , Carsten