I have a borg warner posi unit, and I am wondering if I can swap that into my 86 ten bolt rear.

Actually, I think I answered my own question. The 10 bolt is 7.5-7.625, and the Borg Warner is 7.75 ring gear, and the 9 bolt is its own design.

As long as it is for a 10 bolt rear 3 series carrier you should be fine. Based on the info in your profile that is

And sized for a 7.5 or 7.625 ring gear. Sorry, forgot that part. Knowing what its out of would help a lot.

Well....crap.

The Borg Warner and 10 bolt are completely different rear ends. Parts will not interchange.

Yeah, I know. The guy who sold me the posi unit said he thought it was an Auburn.

I got it, and I said, outloud, "This doesn't look like an Auburn posi at all."

Crap.

If it's a 3 series Borg Warner you won't have any problem selling it. If it's a 2 series then good luck getting rid of it.

It's a 3 series, and it has the 3.27 ring gear still on it. I posted it for sale already. $125 plus shipping.

It's just been an irritating few days. My dashpad arrived damaged because UPS put something heavy on the box, and it got bent and cracked, then I got the wrong posi unit for my car. Dang it!!