What year K5 do you have. My 74 has the body mounts on the inside of the frame rails at that crossmember. I knocked out the 4 bottom rivits on each side of the crossmember, and the hole spacing there was exactly the same as the spring hangers. Just bolt the spring hangers on and drill the 4 holes in the side of the frame to complete the install. This pretty much centers the wheels in the rear wheel wells. I don't think this is possible on newer k5's with the body mounts on the outside of the frame.