These High Energy hydraulic lifters from COMP Cams feature a patented, constant orifice-metering valve that precisely meters oil to the rocker arms. Continuous contact between the metering valve and the precisely coined bottom surface of the pushrod seat is maintained throughout the engine's rpm range, eliminating excessive oiling at high speeds. The pushrod seat is made of a special powdered metal iron alloy, heat-treated for strength and wear resistance. The longer piston is produced with through-hardened steel that provides more bearing surface and increased lifter longevity. These lifters have a lightweight check valve disk that allows for quicker response, resulting in increased engine speed before valve float.