Fits popular engines of 289, 302, 390, 428 cubic inches Designed to prime the lubricating system of a rebuilt engine prior to its first start to prevent the damage of a dry start. It works by connecting to the oil pump shaft through the distributor hole and inserting in oil pump. For use with 3/8" hand drill. * Black Oxide finish * Triangle Shaped Drive End to eliminate drill chick slippage * Aluminum bushing to insert in manifold for centering of tool