I just looked at my '84. I know its got the shorter transmission than yours, so the rear driveshaft ought to be a bit longer. Sitting on 2 1/2" lift Ironman springs, the shaft is 46" long, mounting face to mounting face. Any chance you've got a pre '85 rear driveshaft on there? That might explain it. Did you start out with stock springs? ...and the driveshaft was ok? They did pull out the grease zerk, squeeze out a bunch of grease and then it was "metal to metal?" I did confirm that the short end of the rear spring is pointed forward, I've got 23" from the frame pin to the middle of the ubolt clamp plate and 26" between the shackle and the clamp plate. HTHs