Well guys, I got a new toy today! 6hp Diesel from Carroll Stream. Looks pretty good under the hood (or, wedged under...), and there is lots of space to play with if I feel like adding anything later. This is going to be a working tractor, so I don't want to mess up my pretty decent K-161, so I'm keeping it in the case that I find another O that has a smoker. I even got around to starting a mounting plate! I will be re-locating the tank and muffler at a later time, and just running is sans-hood until that point. It seems like it should work very well in this tractor, as basically everything has been lining up well!
Wish me luck!