#1 check pan rail straightness & end seal and side gasket fitment dry. some rear thin black seals are a bit too long to fit perfect in the main cap half moon groove & the half moon pan itself cutout in the front can be too shallow on some aftermarket pans forcing you to trim the end of the front black seal so with some compression it fits well & sometimes the side gaskets need to be sectioned so the holes in em line up dead on with the block holes & pan special attention to the (4) corner pieces that meet the ends of the black front/rear main seals, trim as needed. I hear good about the MP one piece gasket but ain't tried it (yet).