Chevrolet Gen III/IV LS-Series 3-Bolt Advertised Duration: 270/270 Duration @ .050": 218/218 Valve Lift w/1.70 Rockers: .604/.604 Lobe Separation Angle: 113 Intake Centerline: 109 Valve Lash: Hyd./Hyd. 1500-6500. Good drivability with great mid-range power, also good in turbocharged applications.