This water pump kit comes with a woodruff key, includes the housing, replaces OE#: 0438579, and fits Evinrude Johnson outboard lower units with the following applications: 70 & 75 HP 2 Stroke (1975-1978) Large 4-1/6" Bullet diameter case only. This water pump kit comes with a woodruff key, includes the housing, replaces OE#: 0438579, and fits Evinrude Johnson outboard lower units with the following applications: 70&75 HP 2-Stroke (1975-1978) Large Case Only. The large case is 4-1/6" Diameter. If yours measures 3-1/2 Diameter, this will not work. Comes with a Half Moon Impeller Key, Not a Plastic Wedge key. Please confirm before ordering. If you need assistance, please call or send us a message.