Assembled; For GM LS Engines; 6 Bolt Flange; Aluminum; 280 CC LS3 Stlye Intake Port/ 80 CC Exhaust Port; 0.125 Inch Raised Exhaust Port; 69 CC Chamber Volume; 2.20 Inch Intake Valve/ 1.60 Inch Exhaust Valve; 1.30 Inch Spring Diameter; Single; With Guides/ Seats