That's a tough one, because Vitali is much taller, bigger and hits harder than Rocky. On the other hand the Rock is much fitter and tougher than Vitali. Some guys maybe think now at the Foreman-Frazier fight. The difference is that Rocky is more dangerous than Frazier, because he could knock Vitali out with both hands and Frazier laid more attention on his bobbing and weaving, while the Rock would straight go after the knock-out. On the other hand Foreman had a harder chin than Vitali and more punching power. Marciano would straight go after Vitali and start to make constant pressure. He would non-stop throwing punches against him. I don't see Vitali keeping him away with his jab, because The Rock was insistent and knew only one way: Straight forward. Vitali however is dangerous for him, because he has an enormous jab and punching power. I don't see the Rock taking too much punches from Vitali, because he had a questionable chin(Rocky was dropped by an old, out-of-shape Walcott with one punch and by an old Archie Moore in the first round and those guys were old and out-of-shape for a boxer and would be considered a light-heavyweight by todays standards). Vitali however can take more shots from Rocky, since he has a hard chin(he proved against Lennox Lewis, when he took Lewis best punches without going KO or falling, but with several cuts). I have great respect for the Rock and see him coming constantly after Vitali and I think that Vitali is a worse fighter than the Rock, but I still think that Vitali would knock him out. Vitali knocks the Rock out, before the Rock can knock Vitali out, because Vitali hits harder and has the harder chin. Rocky would stand up after one or two knock-downs, because he has the second highest heart rate and will I've ever seen by a heavyweight champ(first place goes to Frazier), but Vitali would knock him down over and over again, until he would go KO.

Vitali by KO in the 5th round

Cool match up, It would be a crazy fight. Rocky Marciano 5'10 185 pounds 69inch reach vs. Vitali Klitschko 6'7 240 pounds 79inch reach. The size is a major difference, but skills and attributes are what count Marciano has the speed advantage, the power advantage, an iron chin, giant heart, conditioning, and combinations. Vitali was big but too slow and has fought in an era where boxing is on a down hill slop especially in the heavy weight division. Rocky would have a fight because Vitali would stay outside and make Rocky work to get inside but in the end Rocky would come out dominant because he comes from a tougher era of boxing and is one of the greatest boxers of all time. Vitali is one of the greatest heavy weights of this era, but is no where close to being one of the greatest of all time. Rocky would be too tough, too powerful, and too quick. Vitali would give him a fight he would be tough, stronger, and his heart would also help him off the canvas 3 times but he would fall once more and not get up before the count of 10.

Rocky KO no longer then 10

Screw what everyone else is saying size doesn't matter it's the legacy and what kind of fight is in the fighter not the size of the fighter in the fight. Rocky Marciano all the way!!! He was all around the better fighter.

Vitali Klitschko will win this one. The size difference is just too much. Rocky is not a heavyweight by today standard or even a cruiserweight. The cruiserweight now a day weight 195lbs. Rocky weight about 185lbs in his prime. At 5'11" he is short even compare to lightheavyweight today and he has short arms. Their record was quite similar with Rocky Marciano 49 wins with 43 KOs and Vitali Klitschko 45 wins 2 losts 41 KOs. Vitali 2 losts were not really losts. He dislocated his shoulder during the Chris Byrd match and the referee stop the fight with Lennox Lewis due to cuts. Neither man was beaten him up. Unless he get cut or injure his shoulder, I see him using his height to outbox a determine but too short Rocky Marciano. Vitali Klitschko by unanimous decision.

Much as I love old school fighters and a legend at that in Marciano, I think Vitali would handle him. First of all, the size disparity is just overwhelming. I mean that's about 10 inches in height and 80 pounds in weight. And Vitali is not all about size. He has decent skills, strength, athleticism and a hammer of a right hand. Rocky beat all his opponents by his overwhelming offensive firepower, granite chin and stamina. But against a huge opponent who could dish out good offense as well, he'd get pretty much beat himself.

Klitschko by KO in 5

Klitschko.

Rocky.

Draw. these two greats would go at it fer 15 rounds and make it so close yer had to give em a draw.

Rocky drops his ***.