An interchangeable lubricating oil pump for use with two internal combustion engines having different lubrication requirements includes a pump housing and a drive shaft rotatably supported in an opening through the pump housing. A first end of the drive shaft provides a drive gear mounting location. First and second idler gear mounting locations of the pump housing are positioned a common distance from the drive gear mounting location. The interchangeable lubricating oil pump also includes a set of interchangeable gears including a small interchangeable gear and a large interchangeable gear. A first configuration for a first internal combustion engine having a first lubrication requirement includes the large interchangeable gear mounted at the drive gear mounting location and the small interchangeable gear mounted at the first idler gear mounting location. A second configuration for a second internal combustion engine having a second lubrication requirement includes the small interchangeable gear mounted at the drive gear mounting location and the large interchangeable gear mounted at the second idler gear mounting location.