Under his own ruleset, Johnson could beat pretty much anyone not strong/well balanced enough to overpower him inside. He would genuinely struggle in the era of super-heavies, probably, but he really did strike me as a freakishly strong human being. Jeffries was monstrously strong and Johnson handled him, all be it a depleted version. Johnson had speed, superb timing, great strength and was a good hitter. He's another one that fought smart rather than popular on occasion, and it's a testimony to his quality and showmanship that he got the break out whereas the more exciting McVey or Jeanette did not.
Lee Q Murray should be on that list and probably Tiger Jack Fox as well. Throw in Abe Simon for good measure.
In defence of Ketchel, he did walk through Dan Porky Flyn like he was made of paper. He did something to Al Palzer in an exhibition as well. Having said that I could certainly give you the benefit of the doubt and strike Ketchel off the list.
Ali didn't have the best chin, Chuvalo, McCall, and Cobb all had better chins than Ali. Ray Mercer fought some big punchers: Lewis, Klitschko, Morrison, Briggs, Witherspoon, Cooper,
Jersey Joe Walcott...fought some terrific punches, Louis,Marciano,Bivins,Elmer Ray,Lee Q Murry,Curtis Sheppard. etc.
t here is no way you can compare those guys to Ali's chin. he didn't just take the punches and get bveat up he took them and thgen won the fights. Cooper, liston, williams, Frazier, foreman, patterson bonavena, holmes, shavers, norton, lyle, etc. it's no contest. over 20 years and still taking the best punches and winning. the other guys don't come close. :rasta