Competition Cams 26120-16 Beehive Valve Spring Seat pressure: 155 lbs. @ 1.880 inch, Open Pressure: 377 lbs. @ 1.280 inch O.D.: 1.095 inch (Top) 1.445 inch (Bottom), I.D.: .650 inch (Top) 1.000 inch (Bottom) Will work with hydraulic or solid flat tappet cams as well as hydraulic rollers .590 inch maximum lift, 1.445 inch O.D. Originally designed for big block hydraulic roller street/strip engines to allow more rpm