For Small Block Chevy with enlarged lifter bores; .875? diameter; 127g weight; 1.88? seat height; EDM Oil Injection Technology guarantees that the bearing assembly receives constant, pressurized oil flow via precision hole aimed at the bearings; Needle bearings are precision sorted by size to evenly distribute loads, which prevents premature wear and failure ; Durable axle is made from wear resistant tool steel to prolong the life of the roller assembly, especially in high RPM applications