The lower water outlet aids in circulating water at slower speeds. This is of little concern in racing. Most racers point the outlet where they can easily be seen to warn of an obstructed inlet. (Although unlikely with the rear water pickup Johnson uses.) If the motor has a muffler it is usually modified for racing to reduce back pressure. Tuned exhaust only came into use in outboards after WW2. A megaphone exhaust aids in removing exhaust gases, but also waists gas by pulling some of the incoming charge out the exhaust. . .
Garry in Tampa
