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: 0.600in. Installed Height: 1.510in. Seat Pressure: 152#. Open Pressure: 387#. @ Lift: 0.600in. Retainer offset 0.070in. for taller installed height. Basewashers counter-bored to accept a 0.720in. OD seal. Basewasher fits over 0.625in. guide top.