• Mounting holes center to center: 3-1/4"
• Mounting hole diameter: Cleared for 3/8" fasteners
• Mounting flange diameter: 2-7/8"

1) This pump is equipped with 3/8" NPT ports and a male connection on the shaft of the pump (see "More Images" below). If you require a female connection on the pump shaft, please call Catalina Direct tech support at 916/843-1971 for additional assistance.

2) NPT (National Pipe Thread) measurements are an industry standard method of measuring pipe thread sizes. It does not mean that a 3/8" NPT thread can be measured with a tape measure to be 3/8". In fact, a 3/8" female NPT thread measures a little over 1/2" with a tape measure. What is the easiest way to determine positively which size port your pump has? Purchase both a 1/2" and a 3/8" pipe nipple at a hardware store and thread them into your existing pump. Now you know for sure!

3) A very few owners of early Universal 5411 raw water cooled engines report that their engine was equipped with an aftermarket fresh water cooling system. This system had a second Sherwood pump that was different than the raw water pump. The Oberdorfer pump above will not replace the fresh water pump used on this aftermarket kit. There is no known replacement.