I want to buy stainless steel valves for air cooled 1974 Volkswagen 1600cc engines. Intakes are NK-842; exhausts are XH-426 stainless steel with chrome stems and hardened valve tips. In addition to being made from high-quality materials, the valves are swirl polished and fully machined. The intakes are 40mm diameter and the exhausts are 35.5mm diameter heads. The overall length is 80mm. The three grooves on the stem for the keepers are standard Volkswagen type. Quantity will be 200 to 500 per month.