If he faces them in sequence, he will probably lose to the last guy that fights him due to all the shots he takes to his face and body.
I can’t say for sure but I think Carnera, Willard and Baer would be potentially hard and dangerous fights for him. All of those guys could punch hard and the size difference was well beyond marginal. And two out of those three men were world champions themselves. I don’t seem him losing to Luis Firpo. He was way too crude and would likely get caught early by Rocky. Marciano probably beats Abe Simon as well, though on the night Simon went 13 with Joe Louis he could have been tough
He beats every single one and was notably a better boxer than everyone on this list as well as faster, and his conditioning was perfect for fighting these giants. I can just see the Marciano of the Walcott fight exploding inside with that brutal overhand right and making the left side of their face swell. Some of these may go the distance on sheer stalling if theyre a more durable person (Simon and Willard). Firpo, Carnera and Baer and getting brutally knocked out though. Lest we forget Marciano was made to fight taller opponents
Not as durable as Willard, but Buddy Baer is durable I am not sure how this is controversial, Willard was notable for his durability his entire career. He essentially just like Jack Johnson beat the hell out of him for over 20 rounds before Johnson gassed and Willard won. Dempsey vs Willard was just a total wild card and theres some claims that Dempsey even loaded his gloves for the fight. Regardless he fought through a broken jaw and concussion and went a few more rounds despite it. He just stopped when it was clear he wouldnt win
