Beehive Valve SpringSmall Block ChevyO.D. Base: 1.24016/pkg Designed for hydraulic or solid flat tappet cams cams as well as hydraulic rollers.525" maximum lift, 1.240" O.D.Will work with most Small Block Chevy heads with no machining required.SpecsOD: Top 1.065" Bottom 1.240"ID: Top .650" Bottom .825"Seat Pressure: 110 lbs @ 1.700''Open Pressure: 292 lbs @ 1.175''Coil Bind: 1.115"Spring Rate: 347 lbs/inValve Springs; Dual Valve Springs; Single Valve Springs; Beehive Springs; Conical Springs; Valve Lift; Max Lift; Spring Kit.