Lunati Performance Replacement Hydraulic Lifters improve performance and durability for mild racing and street applications. Reduced weight allows the check valve disc to close quicker, resulting in faster pressure build-up. This pressure increases the stiffness of the lifter and allows the engine to rev higher before valve float occurs. Lunati Performance Replacement Hydraulic Lifters have a longer piston than stock lifters, which provides a larger surface area to better distribute the load and increase longevity. Constant contact between the metering valve and pushrod seat controls oiling to prevent the lifters from being over-oiled at high speeds.