Ford Small Block 351W 1969-1996 Cam Series: Street Force Advertised Duration: 259/267 Duration @ .050": 205/213 Valve Lift w/1.60 Rockers: .448/.480 Lobe Separation Angle: 112 Intake Centerline: 108 Valve Lash: Hyd./Hyd. 1000-5000. Street Force 1, good idle, mild street performance, strong low end torque.