Competition Cams 875-16 Reduced Travel Hydraulic Roller Lifters for Small Block Chevy 305 and 350c.i. Engines Originally Equipped with Hydraulic Roller Cam, 1987-Present, Including LT1 and LS Series .842 diameter; 122g weight; 2.60 seat height Designed to perform at higher engine speeds Minimize internal piston movement to allow higher engine rpm Lifter pre-load should be set at zero to 1/8 of a turn of the wrench on the rocker arm adjusting nut for optimal performance