I hope this is ok since the classifides are down at the time. I have a posi disc brake Borg Warner Rear End for sale w/ the proportioning valve. Please email me w/ questions of if you want to see some pics of it. I believe it came out of a late 80s Firebird. Email me Boogada186@aol.com

 

damn, guess I'm stuck w/ it. haha

 

E-bay had one of these a few weeks ago. It had quite a bit of bid activity. These are getting hard to find. You may want to consider going this way...