I do not think a four stroke will fit. You need 3 1/2" from the firewall to the back of the prop. With the rear carb I believe you will run out of space. The Evolution 36 engine's are a tight fit. I did notice that the servo trays for the throttle servo's are made for a left and right setup. Since both engines are mounted the same, I had to move the tray on one nacell to the other side for the throttle arm to line up with the servo and not hit the fuel tank. Other than that, looks like a winner.