I'm trying to identify the rear end in my car. I think it may be from a Chevy II possibly a 65, but not sure of anything as I just began the search today. It is a 12 bolt. I've seen the following ID numbers. F215 on the top of differential facing the rear. 3852980N on the drivers side lower casting. PA 0606 front side of the passenger axle and there may have been additional letters or numbers after the 0606 but I couldn't tell for sure. Thanks for any help what this came out of and gear ratio. Do I have a good combination here.

 

Best bet is remove the cover, count the gears, and get the ratio