My vote would go to Bob "The Bullet" Hayes. He's the only sprinter in history that could run with Bolt imo. Bolt ran a 8.65 in the 4 X 100 relay
during the 2012 Olympics. Hayes ran a hand timed 8.6 on a cinder track in the 1964 Olympics in Tokyo. Hayes took the baton in 7th place
and finished 3 meters ahead of the silver medalist.
https://www.youtube.com/watch?v=mh-YLy_wnrc
I would have loved to see what Hayes could have accomplished with a modern diet,equipment and training regime.