Insane, but the hardest ball I ever saw live was hit by Mark Salas, a catcher for the Twins in the 80s who had a very era-appropriate nickname of "The Chief." (he was native). He hit an upper deck homerun, then was traded the next day.
I was about 5.
EDIT: OMG, for 40 years I've believed Mark Salas was of native decent, because that's what my dad told me when I asked why his nickname was "The Chief." Only now thanks to Google do I learn he was of Mexican decent. There is no joke here, I'm being serious.