Rear End Posi Question

[minendrews68]

I have a stock 8.2 10 bolt rearend under my '68 Camaro. I am wanting to use this rearend but wanting to put a positrac unit in. Has anyone used the Powertrax unit before? If you have what are your view points on it?
Thanks,
Carl

[Rag-Rat]

You can put a 70-74 Nova or X-body 8.5" GM rear end under the car for about the same price it would be to upgrade the 8.2" and the 8.5" is stronger. I have a 3:42 posi 8.5" from a Nova in my 67 Camaro and love it. I just had to shorten the driveshaft a few inches, they are the same width from wheel to wheel.

[b-man]

Just a great idea!

The 8.5" corporate rears are so much stronger than the 8.2", just no comparison there.

The 8.5" rivals the strength of the 12-bolt 8.875" rears, they both use the same pinion bearing.

Personally I wouldn't spend a dime upgrading any of the GM 8.2 10-bolt rears, the Chevy 8.2s are among the weakest of them.

One thing that should be done to any of the X or F-body GM rears is to do a full weld where the axle tubes meet the differential housing. The factory rosette welds (small circular weld in the drilled hole in the housing) are weak and are known to break, even on 13-second cars with so-so traction.

When the welds break your diff nose points up towards the sky, taking out the driveshaft sometimes and rendering the rear axle housing useless and unrepairable.

[hypersport750]

Hate to hijack this thread, but how do yo tell the differance between the 8.2 and 8.5 rear ends?

[MonzaRacer]

Hate to tell ya but the centers are not all that weak on 8.2s, friend of mine used to drag a 64 Tempest in 11.5 lb class(ie 11.5 lbs per cubic in and he ran a 400 pontiac, twisted it to 7500 for launch and speed shifted his muncie at8500 and rarely broke anything, basicly axles or stripping gears as they had to use street gear not pro gears.
But 750 hp and close to 900 lb ft of torque into a diff will tell you that it can be ran with some degree of success.
Personally install a good aftermarket posi, call moser for some good street axles and rock on.

[big gear head]

I have a Lock Right in my truck and it's got about 100,000 miles on it. I haven't had any trouble with it. Don't use the No-Slip. They are junk. The Eaton Posi is better. If you want to road race or auto cross then the Truetrac or Torsen would be better. You might want to upgrade to the 8.5 if you want to put that much money into it.

[TT302Z28]

I have a friend that split his case and broke the ring gear because of the Powertrax unit. The unit puts a large amount of load on the cross shaft that a real posi would have put on a much stronger part of the case.

x2 on the 8.5. There are lots of them and easy to find with the posi already in them.

[chicane67]

I have a Lock Right in my truck and it's got about 100,000 miles on it. I haven't had any trouble with it. Don't use the No-Slip. They are junk. The Eaton Posi is better. If you want to road race or auto cross then the Truetrac or Torsen would be better. You might want to upgrade to the 8.5 if you want to put that much money into it.

Hey Freddy !! Great to see you around the threads !!! I do hope all is well in your garage !!!!

Anyway... I totally second what Freddy stated. I have Lock Rights in the front and rear of my daily driver... with 200,000+ miles on them... and if you knew how I drove and what they have been through... you would understand why we would recommend the Lock Right over the others.

The No-Slip's like to brake small parts from shock loading them... which is pretty typical of off roading and street use/drag racing.

8.2's are not a question of "if" they are going to brake... it's more of a question of "when". I have heard, have seen and have built plenty of 8.2's that will go the distance... but they are in cars that either weight next to nothing... or never... hook the power up. No matter what I stuff into an 8.2 to increase its strength... it's still a ticking timebomb.

I also agree with the idea of upgrading to an 8.5"... you would be wasting your hard earned money dumping it into anything smaller. I always go for the build it once, built it right mentality. Yeah you may spend a few dollars more now... but this is one component you dont want to skimp on. This is a critical item in the drivetrain that you dont want to be rebuilding every couple of years because you tried to bandaid a weaker rear end into something it really isnt up for to begin with.

And FWIW... the cross shaft see no more load with the use of a Lock Right than with an open differential. Mechanically... the loading is the same for either of them.... to include limited slip friction type differentials.

[minendrews68]

OK, now who's got a rear end I need that close to home.......

[big gear head]

I've got 2 of the 8.5 Nova rear ends. They can be built any way that you want.