Finally, we've reproduced these incredibly rare 5 bolt 361/413 Industrial / Heavy Duty Truck / Motorhome water pumps.These were used on most Industrial engines in Generators, Pumps, Sirens, etc, and on Dodge's Heavy Duty truck line, and on many Motorhomes. There are two different versions of these heavy duty 5 bolt pumps. On this one, the diameter of the register that fits into the hole of the water pump pulley to locate it is a diameter of 1.116" Be sure to check the snout or "hub" on your old unit and make sure it looks identical to the picture, some applications may use the other version with the small hub (we carry these also, listed separately.) Completely new part, not remanufactured. Sold outright, with no core or exchange of your old water pump necessary.