I think Rocky hit harder because I've seen him knock guys out cold with a single shot. But while Frazier was the bigger guy, many of his knockouts were more in the TKO fashion--his opponents would be too tired to continue. Between The Rock and Smokin Joe, who packed the harder wallop?
Marciano decisively for me. He hit anything and everything, breaking bones and blood vessels doing so. It was no mistake he was named Rocky. Being hit by him was probably like being stoned by large rocks. In a relentless manner too, given Marciano's nonstop attack.
Marciano. Frazier typically wore guys down with a series of hard shots, but Marciano was known to put someone out cold for many seconds more than 10 with just 1 punch.
Ellis got up from one of the hardest shots Frazier ever delivered to beat the count, the knockdown punch which concluded their first bout. Joe needed a second flooring to put out a badly dazed Bob Foster. Only he, Ziggy and Doug Jones were counted out against Joe after Smoke hit the big time, and they were all outweighed by a margin of 14 to 21 pounds. He did drop Jerry Quarry with a body shot in their rematch, but his best shots seemed to make little impression on Foreman (although his hook did mark up George a bit in their rematch). Jerry claimed after their first bout that Ellis hit him harder than Joe, and Jimmy did have those two knockdowns of Bonavena to support JQ's claim. Vingo, Layne, Matthews, JJW 2X, Charles and Moore were all laid out for the count by Rocky. Louis would have been counted out if Ruby Goldstein opted to administer a full toll for the second knockdown. Savold went to the hospital like Vingo, and likewise had his career ended. What Marciano did to LaStarza's arms is legend. A mutual sparring partner of Louis and Rocky said, "Louis was faster with a barrage of punches. But Marciano hurt you more with one than Louis did with four."
Rocky was bigger pound for pound but Joe was at least 17 pounds heavier ... I see Joe having zero problem flattening any of the same guys Rocky did ... I think Rocky's right and Joe's hook are very comparable ..
I don't think Frazier could knock Walcott, Layne, or Vingo unconcious with a single punch like Marciano did.
Smoke took on a number of opponents comparable in size and stature to Marciano's adversaries, like Ellis, Daniels, JQ, Stander, Ringo and Machen, none of whom were laid out for the count like Walcott, Charles and Layne. (Don't forget that Rex got up from Satterfield's bombs before rallying to stop Bob.)
That would probably knock them down and possibly out, but I don't think they would be unconcious like they were when Marciano hit them.
Nobody ever threw hooks like Rocky. He was just a very special physical specimen. I remember seeing a photo (I forget which fight) of Rocky landing a punch & it was just perfect, every muscle working in union. He achieved leverage like Ive never seen from any other fighter. I love Joe but Rocky hit harder.