40-2035063 Water pump, for the G1600 Hercules industrial engines. Part number 40-2035079 is associated with this same pump ($200.00 refundable core charge included in price).40 2035063 G1600 Hercules water pump. This is the pump called the " high fan position" and has the 2 bolt hub, as opposed to the 4 bolt hub. Part number 40 2035079 is also associated with this style of pump. Pay attention to the position of the hub also, Hercules positioned these hubs differently in relation to the pump housing, which in turn placed the fan in different position for the application needed. This will be item number 1 in the Hercules