Assembled; GM LS Engine; Aluminum; Straight; Rectangular 259 CC Intake Port/ Round 102 CC Exhaust Port; 72 CC Chamber Volume; 2.165 Inch Intake Valve/ 1.6 Inch Exhaust Valve; 1.295 Inch Outside Spring Diameter; Single; With Dual Valve Springs/ Damper Spring/ Retainers/ Locks/ Guide Plates/ Valve Stem Seals/ Valve Guides/ Valve Seats