I just got a 36 1/2 ton with a 112" wheelbase. I have some ranger springs with the shackle and spring hangers. I just want to bolt them up on the 36 frame. I already have a mustang II front end installed in the front from the previous owner. The frame is bare with no bed or cab on it. How do I know where exacltly to mount the hangers? Just measure 112" from the center of the front hubs to the center of the rear axle? any better ideas?