I have a G.P. .40 size cub and mounted the engine to the right, but routed the muffler inside the cowl and out the bottom. With the dummy engine provided mounted on the left side it looks good. I agree with the above post also, do it for the ease of operation also. I used a magnum .70 four stroke, more than enough power with great sound! Fly it around at 1/4 throttle fpor scale flight.