Ford 5/16-Inch Hex Engine Oil Pump Primer for 351, 400, 429, 460 OIL PUMP PRIMER TOOL 5/16" Hex drive end for FORD 351 Cleveland, Windsor Fits popular engine of 351, 400, 429, 460 cubic inches Precision Cut aluminum bushing to insert in manifold for centering of tool Black Oxide finish shaft with Triangle head to eliminate drill chuck slipage Has centered 5/16" Hex cut out in shaft to fit oil pump perfectly