Holmes made it to 48-0 and then lost to Michael Spinks. I think by this time, Holmes was more burnt out than Marciano was. Mind you, Moore was champ at 175 for another ten more years when Marciano defeated him, while Spinks was done in about three-four years following his victory over Holmes. So really, imo, Marciano had it in him to defeat the tougher opposition at this juncture in his career than Holmes. I think Marciano would come to stop Holmes in around 10-12 rounds. It took Tyson four, but since Marciano was smaller, I'd project that it would take him that long to do the job.
you are right...I loved the amatuers because you can see the base talent of a fighter and measure there improvements. A lot of times you see the essense of a fighter in the amatuers. I have seen many fighters ruined in the pro ranks by chosing the wrong type of trainer or management...NICk Wells was one, Willie Dewitt of Canada and Shuan O'Sullivan...I have seen Bowe, Holmes,Tyson,Breyland,Leonard,Antufermo,Bobick,Stevenson,Cooney,Wells,and many others but you can usually spot a strength or a weakness and it is eventually exposed in the pro's unless corrected...but you can tell a lot by a fighter as an amatuer
One word fellas.... JAB. Larry is 6'3" with an 81" reach and one of the best jabs in HW history. That jab would keep Rocky at bay and enable Larry to bang from a distance. Rocky would have to get very close to Larry to do any damage and his 5"10" height and ridiculously short 68" reach would work against him. If Larry was like say Baer, a big man but without a good jab then Rocky would have a very good chance against a slowed down version of Holmes, but Larry's jab would be the key to this fight. Marciano at 49-0 was considerably slower than Larry at 49-0 and didn't seem to be the same puncher that downed Layne and Walcott. It's no coincidence that he retired after the Moore fight. He knew that he was slipping badly. The one punch power was gone and the physical problems were mounting. Fighters like Marciano and Frazier aren't designed for longevity. Like Holmes said of Tyson, " They're like little trucks that burn out quickly". Holmes at 49-0 still had enough left to hold the smaller and slower Marciano at bay to a decision and the jab of Holmes would be the key.