Hi; I put an ST2300 inverted in my .120 and it fit in the mounts that came with the plane with a little carving. The engine runs very well this way with a McDaniels glow system. I would reinforce the landing gear with another piece of 1/4" ply on top and triangle stock. The gear is a little weak on a dirt field or tall grass. I have knocked mine off twice. Great flying airplane. Nub