GM LS engine steam line fittings are available to upgrade the factory steam tubes of your modified LS-powered cars and trucks to update your race car plumbing system. They vent trapped air in the cylinder heads which can cause overheating and hot spots. These swivel fittings are constructed from black anodised billet aluminium which attach to the corners of your GM LS cylinder heads, converting them to a -04AN male fitting. Includes o-rings and stainless steel bolts.