Chevrolet Small Block 262-400 Advertised Duration: 261/269 Duration @ .050": 229/237 Valve Lift w/1.50 Rockers: .555/.555 Lobe Separation Angle: 110 Intake Centerline: 106 Valve Lash: .022/.022 2000-6000. Small Base Circle, Noticeable idle, good for Weekend Street Cruiser, should have 9.0:1 CR, 2000+ stall.