I also have a Shibaura (Ford 1700) that needed a water pump at the same time as my Kubota L245DT. At the time, about 10 years ago, the Kubota pump was about $70 and the Ford was double. Recently, I replaced air filters on both. I got a Kubota filter from NAPA for $11, Ford/New Holland wanted $147.
If anyone knows of a better parts source, I sure would appreciate it. If not, consider this a warning--if you buy a Ford/Shibaura/New Holland make sure you buy it right to cover future parts.