With MLS (Multi-Layer-Steel) .040″ thick head gaskets. SLS (Single-Layer-Steel) cylinder base gaskets and SLS rocker cover gaskets used in these sets are .020″ thick and have .001″ of high temperature viton rubber coating on both sides. Kit comes with all gaskets, seals and o-ring for a complete top end rebuild. Compatible with S&S cast or billet rocker covers.