1968-72 Chevelle, El Camino, Monte Carlo, Big Block headers. Made from 304 stainless steel for maximum corrosion resistance. All tubes are CNC mandrel bent for optimal flow. These headers have 2" primaries with CNC laser cut 3/8" thick flanges. With 3-1/2" Slip-fit collectors. These headers fit perfectly. Long tube design provides awesome torque and street performance. Recommended to use a mini-starter for additional clearance. Mill finish, All TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.