As we have many people come here and ask for plans for the engines, I thought I would make it clear that many of the plans that exist can be accessed Here, the main page of this website. Other sources include within the forums of the engine type you seek. For example, search in the Jet Engine forum for plans of the KJ-66 engine, or seach in the Valveless forum for plans like the Short Lady, that aren't on the front page. Also, contact GLC Inc., Run by two of our members, Viv and Luc, for high quality plans and kits of certain engines, with more to choose from as time goes on. Hope this helps.
If anyone else wishes to add to this, either reply or send me a PM and I will edit in as soon as I can.