OIL PUMP PRIMER TOOL GM Chevy V6 V8 Small Big block Fits all small and big blocks including popular sizes of 327 350 355 383 388 400 406 427 434 454 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. Thick shaft design with triangle shaped end for no slippage. For use with 3/8" or 1/2" chuck hand drill. * Black Oxide finish * Aluminum bushing to insert in manifold for centering of tool