Pretty neat. I was wondering when someone would get around to trying this. Looks like besides your propane tank, that regulator could do with some downsizing and lightening as well. The Honda engines work pretty well, and are all position, but low on power. I'm guessing they have more power than the flathead though. I'd have to look back through my posts to see what my GX31 that I converted turned. For real fun, try a Stihl Four Mix engine, as they are quite powerful. Well, on second thought that wouldn't work without coming up with an oiling system because they use oil in the gas like a two stroke.....
AV8TOR