“Marciano won the bout - knocking out Ali a minute into the 13th round.”
http://www.check-six.com/Crash_Sites/MarcianoCessna.htm
I still think for real Ali cuts him to ribbons. Walcott, Ezzard Charles, even an aged Louis before he wore down and got KO'd busted Marciano up ... Charles literally split Rocky's nose into at the septum, if Marciano had not knocked Charles out very quickly after that happened, the fight probably would have been stopped with Rocky the loser ... one can only imagine what Ali with his fast hands (and again, Ali in his prime was a much better puncher than he is given credit for) would have done. And I don't see Rocky, as tough as he was, getting through Ali's defense in Ali's prime.