Rollers have a larger-than-stock inner bearing race that reduces stress and increases axle life. Each lifter body and plunger assembly is hand-fit and pressure-tested to ensure correct operation. Redesigned plunger assembly withstands forces associated with heavy-duty valve springs and pushrods typically used in high-performance applications. Revised metering device precisely controls oil delivery to top end, ensuring rapid lifter pump-up and reducing possibility of oil starvation to bottom end. HL²T Limited Travel Kit improve cold starts and high RPM valve timing accuracy.