Finding a 10 bolt 8.5 posi In salvage yards

Okay so I just noticed my 71 Skylark has an 8.2, I'm about to start putting my rear disc brake conversion setup on the car and I was gonna try to put a posi in this car, but now everything is on pause. This is my rear end I notice there is no corners on the bottom of the pumpkin making me think this is an 8.2

Anyway, I want to find a whole rear end in a junk yard if I could, I have a list of cars that came with 8.5 rear ends posi and non, but I want to hear from you guys what cars are compatible with our cars. I assume different years and makes have different length housings. I have a 71 Skylark. Thanks in advance.

 

Hemmings posted this article years ago about 10 bolt 8.5 rear ends you can get out of different year cars.
https://www.hemmings.com/magazine/hmn/2009/03/GM-10-bolt-8-5-inch-Differentials/1781844.html

1971-'76 Chevrolet full-size cars
1994-'96 Impala
1971-'81 Buick full-size cars
1973-'77 Buick Gran Sport
1972-'77 Pontiac GTO and Le Mans
1970-'81 Chevy Camaro and Z28
1970-'81 Pontiac Firebird
1971-'77 Olds Cutlass and F-85 and Pontiac Grand Prix
1971-'79 Chevy II, Nova, Buick Skylark and Olds Omega
1973-'77 Chevelle, Malibu and El Camino
1971-'77 Pontiac Ventura and Phoenix
1971-'81 Pontiac Bonneville
1973-'77 Monte Carlo
1973-'77 Buick Apollo, Regal and Century
1980-'94 Chevy ½-ton and ¾-ton pickups
1977-'94 GMC Jimmy and Chevy Blazer



A 10-bolt front axle was used on GM 4WD vehicles as well. It was available in three ring gear choices. Axle codes were GU6 (3.43:1) GT4 (3.73:1) and GT5 (4.10:1). You can find a front 10-bolt in these trucks:


1977-'87 K and V-series half- and three-quarter-ton Chevy pickups
1977-'91 Jimmy and Blazer 4WD
1988-'97 K1500 and K-2500 pickups

Now i wont be find any of the pre 81 cars because people pick those cars up when they see them around here. but i have few 1994 chevy 1500 and 2500 in my local u pull and pay. Now does it fit within the car with the suspension and all that, no idea. i wish it spoke more about what rear end from what years is interchangeable with what cars.

 

The ONLY cars I would check are 71-72 Skylark/GS,and 71-72 Cutlass/442. As long as it has the original rear,it will be an 8.5”. Yours was obviously swapped. What does your yoke look like? The 8.5” that came in the Lansing-built 71-72 Cutlass/442’s look like that onnthe bottom. The picture is not the greatest,so I can’t tell if that is what it is,or if it is a Chevy 8.2”.

 

Im going to take pictures tomorrow.

 

If you get bored and want ride up to SC I got several rears

 

The brake hose bolts into the housing on a 8.5 whereas the 8.2 has a bracket that goes to cover holes, among other differences

 

Here's some pictures I just took.

 

That is the 8.5” out of a Lansing-built Cutlass/442. No need to search.

 

Cars- I have seen them in Pontiac 1972... I think they did the same thing as the 12 bolt chevy deal .. Knowing that in 1973 NONE of these rears would fit...Lesser cars were getting the GOOD rears Chevys with small block v8 and 4 bbl carbs were getting 12 bolt rears Monte carlos, Chevelles and El caminos ... So Pontiac 1972 Lemans I have personally parted out 4 from them... CHECK all 1971 1972 A-body cars in my opinion ....do not leave a stone un-turned.

Jim

 

I looked at one the other day. Pretty stripped and wat was left the only thing worth having was the rear and the ac heater box on the firewall. Guy wanted $350 for the axle. I already have one out of a 72 skylark so I passed.

 

Man we do not even have A CAR to pick apart period. I would be happy to see something like that in our yards.... WE Do not even have rear wheel drive cars in Ohio anymore.

 

I picked all the local yards dry years ago. It’s cool that you guys still get cars like that show up in your salvage yards,AND the parts are good.

 

South Florida has no classic cars in salvage yards period, coming across a buick is like finding bigfoot haha

 

I Believe that!!! I have to look on craigslist to find the VERY FEW guys still parting out some cars here and there.

 

What bolt size goes into the rear end for the top brake hose mounting?

 

5/16

 

Okay thank you

 

How do you guys check pinion depth? I know there's some cool pinion depth gauges out there but they are pricey, a set is 500 bucks. Useful if i set up a lot of rearends, but not for one time. So what do you guys use to measure the pinion depth? Thanks.

 

A better question is do I have to change my pinion gear when I go to a 3 series posi?

 

If you change ANY ring and pinion gear set you always have to check you pinion depth. You can do it with the depth checker...(we do not) Set up bearing is the easiest way to back yard set-up any rear end.
You try the original shim first take a pattern and see where the pattern needs to go and switch your pinion depth according to the pattern swipe of the ring gear teeth.

IF you are only changing a open carrier or broken posi unit to another posi unit then you only need to double check your backlash ring to pinion distance. AS you are not changing the ring and pinion.

Jim
J D Race