I have 84 Chevy I am trying to get an Idea what my truck will look like with 37'' x 12.5 on rear with two inch spacer will the rubber stick-out past the dual wheel flares ? also does anyone know how I can reach Auther Jim Allen I read about the brabnod gear box in his book and I cant reach anybody out there I was hoping that he might know how to get intouch with the old designer of the unit I wonder if he used an existing range box off of a big rig or if it is completly his own . Thanks Everyone.