If motor oil is the lifeblood of an engine, then the oil pump is its heart. If your engine needs a transplant, the S&S three stage oil pump is a great solution for worn out or destroyed stock units. Common causes of stock pump failure are debris and excessive pinion shaft run out. The S&S TC3 oil pump is much less likely to be damaged by either. Additionally, it pumps and scavenges way more oil than stock. S&S suggests pairing with either the early or late style S&S TC3 Cam Plate For Harley Twin Cam (sold separately).