The K in HK30 means it was assembled by Kirby. However for whatever reason, James N Kirby decided to mix features of the Lauson H30 and H30A models. AFAIK the HK30 is pretty close to being an H30A with the mechanical governor from the H30 instead of the H30A's pneumatic governor. However I'm not a Kirby Lauson guy, or even a Lauson guy, so there could be a multitude of other differences. Mr Bonnar gives some information about parts, sources and prices. I think if you follow what he said, you probably won't have any difficulties. (If you do, please tell us about them - it all improves the archives.) Note that there are one or two Outdoorking members who are very familiar with the Kirby Lausons, and if you post your questions, they may straighten us out when necessary.