I paid 200$ for a rear out of an 86' monte ss cause the guy tried to put it in a 59' el camino, so he just wanted his money back for what he paid for it. They typically come with the auburn posi and 3.73's. I just bolted the thing right in but about 4 months later I chipped a pinion tooth. So I had a Yukon ring and pinion put in. I put the rear end in myself since I've got the tools to do it. I paid about 200-300$ to have a reputable builder go through it and check it to make sure the seals, bearings, etc. were all good.