I am just about completed installing my mill (ENCO ,a military surplus). I want to build a hit-an-miss engine but have not found any plans that I like (most are to small for my fat fingers & poor eyesite)
Look thru the galleries and see if there is something you like. Some of them get rather large. Problem with that is they can get awful heavy. If you find one chances are someone will know who to contact for the drawings.