I think most of them had 3.43 posi rear ends. Not sure about disks though. I know that quite a few of the the 90's lincolns and crown vics and tbirds had I think 3.23 or so disks but not sure about posi. My dad and I put one of those in his 54 buick special hard top with a 425 hailhead and a 4 speed hydro trans. It SCOOTS. Either way 2 out of 3, so don't be sad, cause 2 out of 3 ain't bad(shameless Meatloaf plug there).