3. Our ProFiler 12-degree Hitman cylinder heads remain unchanged except for gaining a new set of replacement LSM valvesprings. We sealed the heads to the block using Cometic .040-inch multilayer steel gaskets. The MLS gaskets are well-suited to high cylinder pressures this engine will generate on the bottle, and we've never had an issue with these gaskets maintaining a good seal. We also opted once again for Cometic's intake manifold gaskets because they required only minimal trimming to align with our ported intake manifold.