One of my four tickets that I received while driving my Model A's over the last 50 years, was for blowing my 'Train Whistle'.
While driving through Hayward, California.
At 3 am.
The faster you go the louder it 'whistles'.
It was an original Aermore, four tube. It now sits on a shelf in my basement.
Exhaust leaking was a constant problem with them (they mounted between the manifold and the attached exhaust pipe), so I was excited to see the one that Bratton's sell, which mounts at the rear of the tail-pipe - no leak issues.
So it will be with interest that I will be reading the up-coming responses to your query.