These are reproductions of the cast iron spacers used on the passenger side between the exhaust manifold and factory H-pipe on big block Ford FE engines. They are patterned after the Ford originals but have no butterfly or hardware. The smaller spacer is for the 390 GT or 428 Police Interceptor engines and replaces the heat riser valve which is often no longer functioning or even leaking. The larger spacer is for the 428 Cobra Jet engine, again fitting between the exhaust manifold and factory H-pipe. We also offer the correct “doughnut” gasket for either application. These pieces are next to impossible to find elsewhere, so we make them right here.