For Use With LS Series Or 5.3L To 6.0L Chevrolet Vortec Engines; Mid-Length Style Header; 1-3/4 Inch Diameter Primary Tubes; 2-1/2 Inch Diameter Collector; 3/8 Inch Thick Head Flange With Round Ports; 49 State Legal/ Off Road High-Way Use Only; Ceramic Coated Silver Mild Steel; With Bolts/ Gaskets