Also creating a vein on the leading edge of the guide on the roof of the port to help steer the airflow around the guide helps also. You might experiment with Bondo first to see about size and shape. But I would have the leading edge more blunted than sharp. After flow testing with Bondo, I would build-up with some brass brazing rods to make something more permanent, and do the same for the "lumps" on the floor of the port.
