I pulled this disc brake rear out of a TPI firebird, not sure what year and not sure if it was a 5.0 or 5.7. I want to know whether or not it is posi and if it is worth keeping. The car wasn't running so I didn't get a chance to do a burnout to tell.

One tag that was attached to the rear cover says "SPIN RESISTANCE DIFF USE APPROVED LUBRICATION

Another tag said:
P/N 10040660
RATIO 2.77
SER. NO. 10803

I'm pretty sure it is a nine bolt rear cause I counted nine bolts around the ring gear or whatever. I just want to know if it is posi.

Thanks

 

Spin resistant diff is posi.

Sounds like a Borg-Warner 9 bolt.

 

2.77 ratio is a 9 bolt posi and if you want a strong rear end, it's worth keeping!

Miles
www.9bolt.com

 

I can't afford a rebuild right now. What are the chances the posi is still good and how strong are the 9-bolt posi's?

 

Most people couldn't afford to rebuild a 9-bolt since parts are rare and expensive. However, they were supposed to be stronger than the 10-bolts, so you may be in luck.