switch to an 8.5, or keep my 8.2

J

joeskylark

Member
I have a chance to pick up a 10 bolt 8.5 rear from a 72 skylark for next to nothing. I currently have an 8.2 in my 70 skylark. Both rears are non-posi. Does either rear offer anything more in terms of performance, bigger brakes, durability, cost of parts to rebuild/convert to posi? Which would you rather rebuild, the 8.2, or the 8.5? Big gear head, jump right in. Thanks
 
Youor 8.2 will be the BOP, which is stronger than the Chevy 8.2, but parts are more expensive. You do have axles retained by the bearings instead of c clips, which is good if one ever breaks.

The 8.5 is stronger than either 8.2 rear end. Parts are cheap and everywhere, even in the latest GM trucks. The '72 8.5 that you found might have pressed on axle bearings and no c clips. If it has c clips then all of the Chevy car 10 and 12 bolt brakes will bolt on to it (except Impala). There are many after market parts available for it and you can easily upgrade it to 30 spline axles if you want.
 
The rear that is available is from a '72 skylark. Are you saying that if it has C-clips it is more desireable or less desireable? I thought the canadian built c-clip rears were to be avoided because of the limited aftermarket parts. This rear also has 2.56 gears. If I get it, and get a new posi, I would like to use 3.42's. Am I limited in any way. I already know that if I get a new 8.2 posi unit for my existing rear, I cannot get 3.42's.Thanks.
 
Axles with pressed on bearings are better because if you break an axle it will stay in the rear end. If a c clip axle breaks it will come out of the rear end and you will loose the wheel. Some of the early 8.5 A body rear ends had pressed on axle bearings. These rear ends still take the same internal parts as the c clip rear ends.

You might not be able to get the 3.42 gears for the rear end you have now, but you can get 3.55 gears.
 
There is zero aftermarket gears or posi carrier availables for the 68-70 buick 8.2 rears and used are tough to find and spendy. they are a buick only rear and are not BOP. the BOP axles in Buicks were from 64-67 only. the 72 skylark will have bolt in axles and posi carriers and gears are readily available. I just finished building a 8.5 for my 65 project. used S spring posi carrier was 100.00 and a good set of used GM 3.42 gears was 75.00, carrier bearings 50.00 and a pinion install kit was 50.00 the brakes that are on your 70 axle will bolt right onto the 72 skylark axle. hope this helps. Bob
 
Bob,
I wasn't aware that the Buick axle was special. I thought that the Olds was the only one that got a special rear end from '68 to '70. I have sold BOP parts to guys with '70 GSXs and other Buicks and they worked. Is there something that I'm missing?
 
Yes

The 1967-1970 Buick rears all have totally different gear sets. the inner pinion is 1.875 like the same bearing as 489 mopar 8 3/4" gears. YOU CAN however get positraction units . I have supplied them for a while now. Gears, like stated are only used or if you incredibly lucky to find a set of NOS gears on a buick dealership shelf somewhere in BFE...lol .

The 8.5 buick is a very good choice for a build. We soup <lol them up all the time with Moser 30 spline axles and Eaton 30 spline performance posi units and or full 30 spline spools for racing. Good choice of gears and parts available. Good luck, Jim -J D Race
 
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