S&S's new, 1981 thru 1999 style oil pumps for Big Twin are CNC machined from solid billet aluminum for strict manufacturing tolerances and high-gloss polished for that "different look". S&S oil pumps route surplus oil back to the main supply passage rather than the return to eliminate unnecessary filtering and offer the opportunity to upgrade earlier engines to the 1981-up oiling system. This oiling system splits bottom and top end oil supplies, increasing oil pressure to hydraulic lifters and top end. Another simple, optional modification will improve primary chain oiling in 1965 thru 1972 models. The oil pump cover is compatible with both OEM steel oil lines as well as conventional neoprene line to insure a simple installation and professional, uncluttered appearance. S&S oil pump assemblies come complete with all internal parts assembled, gaskets, drive shaft with keys and snap ring, mounting hardware, check ball and pressure relief valve assemblies. For those who want everything to be 101% there is an oil pump assembly complete with drive gear, breather gear and shim kit available.
Note: For maximum flexibility, S&S oil pumps provide optional location for the oil supply fitting. Dyna's, late FL's and other models with oil tanks below the transmission should utilize the stock location. Otherwise, under certain circumstances air could enter the oil pump and interfere with engine lubrication. No provision is made for rear chain oiling on ANY S&S billet oil pump. The billet oil pump for 1936 thru 1976 Big Twin is equipped with an adjusting screw to control primary oil metering. Oil pump assembly ZPN750604 is as supplied with all S&S V-series Evolution style engines and features an universal cover with top and bottom feeds.