My GF's 68, stock susp, no body lift, stock 15x5.5 wheels, 31x10.5x15, no rub even when flexed. I don't think you could get any more tire without some fender mod, you could run a 245x75x16 which is same height as the 31x10.5 but not as wide and would be a better choice if you had a set of 16" wheels you like.