As far as I know, "they" never made a 2.56 12-bolt posi. I had this rearend custom-built by a guy named Art Houser in Pennsylvania in the mid-1990's. He died several years ago, but he used to have quite a reputation. You can still find traces of him on Google (he also went as "the rearman" although I'm not sure I would've taken that moniker for myself...) Monzaz has rebuilt the posi unit from this rearend, maybe 6-8 years ago. I daily-drove my car 100+ miles/day for many years with TH400 and EFI. Adding a lockup would have probably added 2MPG for me, although you have to be really careful with your cam profile. I have no idea what the difference is - like I said above mine was a custom-made from all of the best stuff around. I guess I thought '68-'72 were all pretty much the same design & construction. If you have a particular point of concern, I would be happy give any details about this rearend. In order to comply with board rules, I'm going to put an ad in the parts-for-sale for the rearend soon. -Bob C.
I know I can build you one I think we have a housing here with 2.56 and will just install a Eaton posi and new bearing blast the housing and you can add your breaks and go. We can do the brakes also. Jim J D
I can bring you the housing with 2.56 in it and a 3.64 posi to install in a 69 housing and a 3.91 to put in my 65 Wildcat housing.
12 bolt Olds and 12 bolt Chevy BOTH came with Posi units from the factory...NO need for custom anything. They just came that way. I actually made a custom 2.56 2 series 33 spline posi for a Buick guy in Florida that was racing that gear in a Turbo car...??? I do not ask I just get it done if possible. Jim
