Another easier way to solve the inverted engine problem is to use a Perry oscillating pump. It only supplies the amount of fuel the engine needs. It operates on the reaction of the torque caused by the firing of the engine. As the engine oscillates back and forth the pump supplies fuel. I used one on my Goldberg Cub. Had a saito 50 mounted inverted and with the tank mounted high tended to flood at low rpm or just sitting when the tank was full.