Obviously Bugner would lose to virtually any ATG heavyweight champion in history. I could see him going the distance with them all,though. Durability was Joe's middle name,and in his prime it would have been a very tall order to beat him inside the distance. When he got knocked out in his first pro bout,he was only seventeen years old,and his stoppages at the hands of Earnie Shavers,Frank Bruno and Scott Welch came years after Joe's prime.
Well Bugner fought in the 70s so that makes him almost unbeatable by definition. No fighter from the 1980+ period has a chance against Bugner. Leaves the classic guys. I'd favor Dempsey to knock out Bugner. He was active in the 20s so that gives him more classic (=mythical) power by definition.
Well obviously Wlad, as Wlad KO's everyone and if you think that's not true it's probably because Wlad is white and you hate white people.
He was a mad spoiler though..His chin was very proven but he could be hurt...Guys like Tyson and Lewis would get him out of there.
I think Louis, Lewis, and Bowe would all have Joe out of there. I don't see Tyson doing it though, Joe wouldn't win but he'd frustrate Tyson in a points loss.
Foreman and Lewis would be my best bet. For the likes of Tyson, Frazier, tua etc, I can see Joe having shaky moments early but ties his man up and the durable Bugner survives and even starts to take a few rounds in the second half of the fight