5. The M-6009-427F BOSS block uses special head gaskets (M-6051-CP331 or M-6051-S331) available only from Ford Racing or Summit Racing Equipment. And remember, they are right and left bank specific. They do not interchange. Look for the “1031L” or “1031R” and “UP” on each gasket. These gaskets are not shaped like traditional small-block Ford head gaskets.