S&S Hydraulic Tappets fit all HD Evolution, HD big twin engines and 1986-'90 Sportster models. They also are used in S&S engines for 1966&-'84 big twin chassis. These tappets feature numerous significant design improvements and are perfect for stock replacement as well as high performance applications.Features and Benefits: Larger inner bearing race reduces stresses to increase axle, bearing, and roller life: the S&S inner bearing race is .123 larger in diameter than the raceless roller axles currently used by some manufacturers. Improved inner race-roller design allows use of more, and larger bearings to increase load-carrying surface area, further reducing stress and wear in the critical roller area. Redesigned plunger assembly better withstands forces associated with heavy-duty valve springs and cams typically used in high-performance applications. Revised metering device precisely controls oil delivery to top end, insuring rapid lifter pump-up and reducing possibility of oil starvation to bottom end. Each lifter body and plunger assembly is hand-fit and then pressure-tested to insure correct operationSet of four, with HL2T limited travel kit.