Cometic GM LSX Gen-4 Small Block V8 .054in MLX Cylinder Head Gasket - 4.200in Bore - RHSCOMETIC MLX (Multi Layer Stopper) gaskets utilize an integrated stopper layer for combustion chamber sealing and improved clamp load around the cylinder without increasing bore distortion. MLX technology can be found in some head gaskets and are made from the same materials as our MLS Head Gaskets. No sealants or re torque required.