The trouble is, it wasn't a very long time. Less than three years as champion. I mean even Tyson reigned longer than that and we don't need to tell you how crap he was.
Marciano was a "cruiserweight" by today's standards (188 lbs).....but the same height as Tyson, but a shorter reach. Assuming different / better training & nutrition of today, he could probably come in at 205 lbs, the weight Frazier was for the Ali FOC. At that weight, he could probably hang in with opponents up to 220 lbs...due to his hitting power and will to win.
Exactly who I was thinking of, mac. Something like 42-0 till he ran into the teenage Cassius Clay. I mean ... who had he been fighting?
No. He ended it beating up a fat British level light heavyweight with health problems and still he took nine rounds to get him out of there. If Tyson had been fighting Don Cockell in Tokyo, especially with his own referee, I think he might have prevailed even if he hadn't trained, was taking all the drugs in the world and had a dose of knobrot.