Im in the minority here.. I say calzaghe UD, Marciano have struggled against lesser opponents than Calzaghe through his career, who also came from the Middle/light-heavyweight divisions, Calzaghe in his prime had very good punching power and flashing speed, he might not hurt the rock, but he could definitely cut him open..
Clazaghe has a fine chin, but wouldn't stand up to a freakishly powerful small great HW like Marciano.
calslappy has eluded much quicker fighters why not marciano I would only assume 1 punch in the chest and its night night tho
Marciano couldn't KO plenty of lesser fighters, with far less durability than Calzaghe. Calzaghe wins 118-110-ish, but overall Calzaghe easily last the distance and easily outlands Rocky.
Calzaghe would easily beat Marciano , he did this to peak superman Roy Jones: This content is protected Only Joking, Marciano KO1 Calzaghe
Remember that forearm that Calzaghe caught from Jones? Now imagine that being a straight right hand instead, except by the Rock. Anyway, Marciano by K.O.