For mounting, the 1/2 ton frames have a significant kick-up right above the axle, this allows adequate travel between the top of the axle and the bottom of the frame. It also lowers the truck's rear. I 'flipped' the 12 bolt GM truck rear end I put under my 53 to the top of the springs to lower the truck. This also means that I had to notch the frame to provide adequate travel.
His 49 is a 3/4 ton not a 1/2 ton. He has a different frame and does not have the same degree of arch at the axle. Also his frame is 11" more narrow than the 3100. And his springs are located outside the frame. A bunch of difference between the two.
