BoxRec

Jersey Joe Walcott
Ezzard Charles
Larry Holmes

Modern rules, of course.

Knocks out Walcott and Charles, IMO (though Charles would stand a decent chance of hearing the final bell. Walcott would be caught at some point).

Not sure with Holmes. Thats harder to predict.

Dempsey by KO in all 3 matches. Actually see a peak Charles giving him more problems than Holmes.