Chevrolet Gen III/IV LS-Series 3-Bolt Advertised Duration: 278/297 Duration @ .050": 230/250 Valve Lift w/1.70 Rockers: .625/.625 Lobe Separation Angle: 113 Intake Centerline: 109 Valve Lash: Hyd./Hyd. 2200-7200. Hot street/strip with blower or large NOS system, big mid range power.