I have a lightly used 3.73 ring and pinion set with an Auburn High Performance posi unit for sale that came out of 10 bolt. I had this in the car for a 3k miles. I then added a supercharger and decided to upgrade the read end to a 4.11 12 bolt. Has been sitting in my garage for about a year; came out of the car running without any issues. This is the stronger clutch style posi unit and complete gear setup. I will not split this up, will only sell as a complete unit. gears new are about $150; the posi is about $400. Asking $400 for the complete set up. I also have a bunch of pictures if you would like.
Part # for gear: GM-14092111-11-41-7 5/8
Part # for posi: 542040, High Performance Series, 3.23:1 & Up

Here is a link to the pictures:
http://photobucket.com/camaroposi

If you have any questions feel free to call (650)241-8963 Thanks, Mike