Well,
I have to cheese at my own observations
Took the F4F thru the same 20k dive and stress sound pull out maneuver and it flew 30 miles faster before the stress sound engaged when I then reduced throttle and rpms, pulled on yoke and she swung skyward with barely a wink of an eyelash.
Maybe it is the pilot stuff trim, engine speed, amount of pressure on yoke??? Anyhow, Wildcat went to 598, but did shake, at that point I pulled up.
Going back to do some more extreme stuff with the Brew and see what occurs....... (writes letter for wife...just in case, it's in my upper jacket flap pocket).
{edited after second flight comparison}
I played chicken with the sea (not to be confused by Charlie), from 20k in Brewster this time 20 mph faster than before at 585 mph and observed the same shakey behavior as Wildcat, all else was the same except this time I did have significant blackout when pulling up.
I have to conclude that my assumption of the stress sound indicating redline performance for the plane seems to be distorted (not accurate in film viewer) therefore I do believe that the person (virtually) flying the plane and knowing its limitations does add to variations. However 15 mph more would most likely involve some good trim management, correct fuel load, altitude start and angle of decent (not saying impossible).
It is just that the most amazing things that I have perceived about the Brewster have been more in line with its handling.