has any one ever re drilled and pined a set of springs to move the rear axel further back on them? pros? cons? the reason i ask is i have a 85 excab that is sitting on 63' chevys and i want to bob the bed but with those looooong springs its pointless id be taking of like 3in. so im planning to move my foward spring mounts foward like 8in and then move my axel 8in back on the springs, allowing me to use my old rear spring mounts and allowing me to bob back to the mounts. pleaselet me know if there is a problem with doing this before i start tearing things apart.