I think Marciano wins. Even with a size advantage, I think you have to be a great fighter to beat Marciano. I don't think Ruddock/Morrison/Bruno level fighters are enough to beat Rock.
Im not so sure about that. It's hard to see marciano imposing his strength and power against these monsters. And while he wasn't as face first as some claims, he wasn't a defensive genius either. Could he really take bombs from these big guys and keep chugging forward?
Well Ruddock had better catch him inside of 6. With every passing round, Marciano's stamina would become more a factor.