posi unit donor

[Someone_Much_Cooler]

I heard you could use the posi unit out a few other gm cars in the grand nats, any idea what ther cars have interchangeable posi unit wit the grand nat's 8.5-28 spline axel? I heard chevy s10 8.5 rear end with 342 gears, certain fbodies, 93 b bodies?

 

[maddog20_20]

S10s are 7.5s in the older models -- I think they started putting "some" 8.5s in the 95s and above. I have seen a couple in the round body 4X4 blazers. The RPO code for 3.42s is GU4

 

[Oldsmoletick]

First off it will need to be an 8.5 rear, so that rules out any f-body newer than 81. Some of the full size cars had them but, you'll need to find one that is a pre 88 (they switched to 30 spline in either 88 or 89). Same goes with the full size trucks. Other than that, a corporate 10 bolt 8.5 posi shouldn't be hard to round up, for a decent price. (oh beware of some on ebay lol, chev also had a 8.5 front axle, people will call em a 8.5 10 bolt posi, but they don't have the provision for c-clip axles).

 

[pontiacgp]

just make sure those posi's arn't a gov lock

 

[Someone_Much_Cooler]

Not even sure what a gov lock is? How do i know if its a 8.5 rear

 

[86_olds]

so if i can get like a 98 s10 4 cyl to donate the posi unit it will fit into my rear end >?

 

[pontiacgp]

Not even sure what a gov lock is? How do i know if its a 8.5 rear

this is a gov lock... and you can measure the ring gear if you're not sure it's an 8.5

 

[85GPLef41]

chev also had a 8.5 front axle, people will call em a 8.5 10 bolt posi, but they don't have the provision for c-clip axles).

how do you tell the difference visually?

 

[Oldsmoletick]

You'd have to get a close look at the side gears, look for the groove for the c-clip to seat in.

 

[Someone_Much_Cooler]

so when im in the yards look for a 1st & 2nd gen fbody, 80-86 full size car (caprice) & full size trucks (Tahoe/Suburban), anything else? I'm assuming it must be the v8 option?