I just found a nice 10 bolt 8.5 open rear end with a 3.08 gear. I want to change it to a 3.55 posi. The rear end is out of a 72 nova. I have read somewhere that you can go to your local pick and pull an still find posi differentials and maybe even a gear set. Can anyone tell me what year, make and model of car or truck i can look for that might have some parts i can use. I realize i may have to pull off a lot of covers but that is ok. Thanks for any recomendations.

I had a 3.55 in my 79 vette (stock)

I think GM stopped making the 8.2" after 1970 and used the same center housing for the 8.5" through 1990.

Here's a link for helping find a posi 8.5":
http://www.buickperformance.com/posi.htm

Truck diffs are of another design than auto diffs. If you do find a diff, look for the limited slip tag on the fill plug, if still there to signify posi carrier. Otherwise, pull the cover to check then read the numbers stamped on the ring gear for ratio.

Most any 8.5 carrier will match up. When pulling pinion, take its shim beneath the bearing as the bearing underneath the gear will need to be pressed off for a new bearing. If possible, do a backlash check for reference so when you reinstall it, you can try to get the same backlash. Take carrier shims with you to help set backlash as new gear set will need reshimming to set backlash in your housing.