Why would you want to mount the engine sideways?? Looks wise on this plane, it might even look worse with the engine sticking out on the side because you would have to chop away the sides of the fuselage for the engine to clear which would look like crap. Also there won't be room for the standard muffler. You would have to go to a a pitts style muffler to keep from interferring with the nose wheel. You would also have to change the engine mount but with the wheel assembly sticking down I don't even know how you could do this. If you did find a mount that would work, you would now have to install new T nuts inside the firewall which isn't easy to do once the fuselage is built around the fuel tank compartment. Personally I don't see any advantage and I wouldn't bother.[8D]