Jim That is a G80 GM gov lock posi ...probably 28 spline as i think the 046 case is 28 spline. 10 bolt 8.5 unit ALL truck G80 units are 3 series. THIS is not a unit to use in a performance burn out application. It is for a truck and should be left there. OR if you have a car your going to drive through the snow it will work great. Jim
That is a 2-series posi carrier for 71-up 8.5" 10-bolt,for 2:41/2:56 gears. It can be used for numerically higher gears,with the use of a ring gear spacer #MRG908A.
MAke sure you take that unit apart and check the clutches and reshim ...I am sure it will need it. Jim
They all need it,even a low-mile unit. I had an NOS one,in the GM box,and that needed it too. Those units were assembled very vaguely. Not aggressive at all. I've added as much as .070" to each side before.That's a bunch.
Take it apart first.Sometimes that clutches are mint,and you only need some shims. Just keep everything noted as to which side & where they came out of. A clutch/shim kit is about $200.00,and they have the diamond-textured pattern like the original Eaton 12-bolt Chevy clutches. Very nice.
