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change to posi


Veteran Member
Jan 6, 2013
Canon City, CO
sorry for re-visit; found this thread on a search...will these posi locks on the stock 8.5 10 bolt stand up to the torque of a mild 383? (say ~400 ft lbs @ 4000 rpm with TKO500 trans)

big gear head

Veteran Member
Jul 30, 2001
It should hold up well if the clutches are shimmed correctly. If it's too loose it makes the gears weaker because of where they make contact with each other.


Veteran Member
Lifetime Gold Member
Jul 26, 2001
Santiago, Chile
When I did mine, I got a used posi and an installation kit (bearings, shims, gasket, etc). If you are going to keep your current pinion/gear combination maybe you won't need a complete installation kit, but at least get new bearings for the carrier and some shims so you can play with the carrier position.

The only "difficult" part is to get the carrier in the right position if you have no experience doing it, it will be easier if you keep your current pinion and gear and harder if you are throwing a different set. Is not that it's "hard" it just takes time and be cool and patience to get it right.

besides that, it's a piece of cake :p

note: remember that gear bolts tight in the other direction, so please check if your torque wrench works ok (it already happened to me that the wrench only worked one way).

Thomas Clark

Veteran Member
Jan 17, 2010
Lexington, Ky
I just installed a Eaton posi into my 76. I followed all the instructions from this thread and think I have it correctly. One question though. What is the oil capacity? is it 1 quart or 2?