I have a base rear-end from my old 67 Riv, swapped this one out for one with the posi. Ran great while it was in use, still will. It is the non-posi version, I think that makes it 3.08. Pinion thread cut 1/2. Come and get it for free! Also have a few other odds and ends for Rivieras that you can peruse through. Zach