Inverted engines CAN be prone to flooding if the carb centerline is below the centerline of the fuel tank. But it's not always the case. Most properly designed planes work really well with inverted engines. When the tank is higher than the carb you tend to get syphoning problems, This can be cured in a number of ways. Some people pinch or clamp the fuel tubing to the carb until they are ready to start the engine. Some people purchase fuel regulators like the cline or the ironbay ones. Just do a little research into the plane and engine you are planning on buying.