You would have to give george the edge in most of the fights but that would be george foreman the finished article. marciano had a way way tougher route to the title than foreman did. there must have been a reson for that. george fought no unbeaten guys (until frazier) and only one guy heavier than he was, marciano was outweighed 27 times and fought 2 unbeaten guys in his first 5 fghts, one former champ and rated prospects like layne and lastarza in 50-50 fights. As for george foremans run to the title, chuvalo was about the only name he fought and Frazier was georges first 50-50 match up. roberto davila was 21-15 when he went the distance with 7-0 george but in his next fight davila was stoped in 4 rounds by feather fisted joe bugner proving foreman was not always a monster.
Im not sure Foreman would have the Stamina to catch Walcott. This would actually be a great dream match. Other than that I think he wins all the fights.
Foreman vs Marciano Let me put it this way. I think '69-'71 Frazier, plus a referee that is strict about shoving off ... well, I'd still favor George, but if you could fight 'em three times, I tend to think Joe would win one. I think Rocky was a bit less square on than Frazier, so probably a little harder to upper cut; so I give Rocky even a better chance. I'd favorGeorge, who I think would be a monster to have to come in to; but not long odds -- and if Rocky won, I wouldn't be at all suprised.
Charles could have pulled a Jimmy Young but not the Charles that fought Rocky ... Walcott and Moore could have both been trouble ... head to head Foreman destroys Marciano early ... it's all styles ...