Yes, you can power that model with a glow engine, but you will need to beef up the nose to handle the vibration from the engine. 1/16" ply to at least mid way through the wing saddle is my recommendation. A .40? How about a .09 to .15 max! The wing has a 36" span and the tail appears to be 3/16" square sticks. Compare the size of the rudder hinges with the structure. A .40 will tear this apart before you have a chance to realize it's happening.

John