Giving Hart every benefit of the doubt is there anything he did as good as Rocky ? If he goes at Marciano balls to the wall I just cant see him lasting that long ... maybe a Frazier/Quarry type of thing ...
Would be a really fun, awesome war that lasts a lot longer than many think. Sure Marciano was better, but Hart could punch, could take a punch, came to fight in shape, could keep a fast pace, and could come back from being hurt and cut and continue fighting hard. He proved this time and again in war after war. Don't think for a second that this isn't an exciting scuffle or that Marciano doesn't take some serious licks too. Might actually be a brawl with a decision for Marciano, rather than a knockout.
I think Marciano eventually stops Hart brutally, but it would be an entertaining fight. Marciano's defense is his biggest advantage over Hart. These are two very willing guys.
I think one has to pick Marciano. Hart losing to Burns does not speak well of his chances against the bigger and much better Marciano.