I don't think any KO's him in those weightclasses. A decision would be the most likely outcome of a loss for him.
Not at 140 Hearns wouldn't. How would he even get down there? LOL @ Pryor. Floyd would not brawl with him.
Might not matter, Pryor would be giving him angles, throwing unconventional punches, and out working Floyd by a large margin. But honestly this is close to a pick em fight for me as I can think of.
I think Duran, Pryor, and Chavez could all possibly beat Floyd, but not KO him. Mayweather could masterclass them on a given though.
I misread the thread title and thought you meant Floyd Patterson. I had about 20 ATGs ready to send in to KO him.