Unibodyboy,Many times the bolts have been overtightened and the holes dimpled in, then you are not getting good clamping forces on the flats between fasteners. also if the holes are dimpled in, when you tighten the bolts it will tend to want to squash the gasket outwards giving poor sealing results. you may want to remove the pan and flatten all the surface around the fasteners. Then do not overtighten but go around and around evenly snugging them up to spec.