Stainless Works Headers Only 2" With EGR Fitting, Factory Connect2001 03 Chevy GMC 3 4 Ton Truck 8. 1L, headers. All tubes are CNC mandrel bent for optimal flow. Made from 304 stainless steel for maximum corrosion resistance. Features 2" primary tubes and 3" collectors, connects to factory head pipe and cats. Headers are fully TIG welded and back purged. These are TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.