1999-02 Chevy, GMC Truck 4.8, 5.3, 6.0L, (4WD Only) Truck headers. Made from 304 stainless steel, for maximum corrosion resistance. All tubes are CNC mandrel bent for optimal flow. 3/8″ CNC laser cut flanges. These headers come with air tube fitting on primary and 1-3/4″ primaries that flow into a 3″ slip-fit collector with O2 bungs welded into the collector. Kit includes High temp RTV silicone, 8mm Header Bolt Kit. This is Headers Only. Mill finish, All TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA. Headers Only.