Contain all the components that need to be installed on the pinion shaft for the specified year group. Kits for 1939-'53 and 1954-'77 can be used in 1972 and earlier engines to speed up the oil pump by 25% for more potential oil volume, since S&S oil pump drive gears are of the 1973 and later 6-tooth design. Color coded to match the OEM color chart for pinion gears Biggest; Orange 913-760 Black 913-7611, Average; Blue 913-762, Greeen 913-763; Smallest; White 163-111, Brown 913-764, Yellow 913-765