The reason I raised the issue of Stevenson was on the basis of one punch that sticks in my memory. He fought (I think) an Eastern European heavyweight, a huge hulk of a man in the early rounds of the Olympics; in the first round Stevenson hit him so hard he was lifted clean off his feet and deposited on his back, out cold. The punch was an orthodox left jab. He would certainly have threatened any of his contemporary pros with that kind of power.
Tim