Assembled; Chevy 7.4L/454 Cubic Inch Engine; Aluminum; 290 CC Intake Port/ 110 CC Exhaust Port; 100 CC Chamber Volume; 2.19 Inch Intake Valve/ 1.88 Inch Exhaust Valve; 1.55 Inch Spring Diameter; Single; With Guides/ Seats/ Springs For Hydraulic Roller Cam; Not For Sale Or Use On Pollution Controlled Vehicles