I got a 12 bolt, drum to drum, out of a 70 Chevelle with 3.08 and an open diff for $400. But I got damn lucky. I took me a year and a half to find it. I have seen them sold for $400 just for the housing. Most of the ones I found were right around $800. One guy had one out of a 72 El Camino 2.73 open diff, he wanted $1000 for it. You can still find good deals on them, but it's getting harder.