Our rails are 38.5" wide on the outside, and 33.5" inches wide on the inside(measured at the front spring hangers), making the rails each 2.5" inches wide, which leads to the measurement for pads being 36"(center to center), by your math, with my measurement on the rails, the rear end needs to be 50.25" or 50" at the axles, pending an 1/8" thick rotors mounting on the axle. We should start a business doing this Tin, we really got it down eh? :read2: It was funny today when I called up Bill and ordered the suspension and he brought up brake width, made me go #-o but it turned out to be no problem at all.
-Ryan