Abstract: Metal products are taught that comprise integrally formed resin seals. The fastening strength of a rubber or synthetic resin seal is increased because the resin seal is formed during a casting operation. For example, an unvulcanized rubber or unhardened resin seal member (9′) may be temporarily secured to a metal mold (A1) and heat from the molten metal vulcanizes or hardens the seal member (9′), thereby integrally forming a rubber or synthetic resin seal and a metal molded body. Resin seals can be integrally formed on metal products having a variety of shapes, because the resin seal will melt and integrally form with the metal product during the die casting operation. That is, the resin seal is adhered to the metal product by a diffusion or seamless bond. In one representative embodiment, an engine head cover is die cast and a plurality of bolts protrude from the engine head cover.