The Evolution 36 engine is recommended

You might could use a 46 or 55 two stroke

And here is an article about using the Saito 56

http://www.horizonhobby.com/Articles...ArticleID=1616

And if you can put a 56 in the plane, you can put a Saito 62 in it just as well

The Saito 72/82 have the same mounting holes but are getting a little too big heavy and powerful for this airframe