Designed for maximum performance. Feature interference-wound, double-chrome silicone springs; heat-treated steel base washers. Available in a complete set for one engine. Include steel retainers. Made in the USa. Require machining of valve guides for special seals. NOTE: May require R-Style valves to achieve correct install height Type: Intake / Exhaust. Valve Lift: 0.415in. / OEM style. Installed Height: 1.375in. Seat Pressure: 129#. Open Pressure: 272#. @ Lift: 0.415in. Spring Base: Fits 0.625in. Guide.