Williams was a 6'3 215 pound power puncher with some good boxing skills, but kind of chinny. Marciano's style required him to come forward and possibly take shots and he'd be the smaller man, however, he had the punching power to lay Williams out. How does this go? Let's assume that Williams came along in 1952 or so and got a title shot against Marciano.
Not sure if Williams was really "chinny" in his prime. Lost to only Bob Satterfield, and Liston (2) by k.o., prior to "post gut-shot" fight against Ali, when he was just a "sitting duck". Could the Rock k.o. Williams? Very Likely. And no one k.o. the rock as a pro. 1954-06-22 : Cleveland Williams (33-1) 201½ lbs lost to Bob Satterfield (33-16-) 176½ lbs by KO at 1:03 in round 3 of 10 Location: Auditorium, Miami Beach, Florida, USA "Bob Satterfield, Chicago, spotted his opponent 25 1/2 pounds and knocked out Cleveland Williams of Tampa in 1:03 of the 3rd round in a scheduled 10 rounder at the Auditorium last night. Satterfield unleashed a murderous barrage of punches in the 3rd round to flatten Williams. The final punch was a left hook to the chin. After the fight it took almost a full minute to revive the 20 year old Tampa heavyweight." -Associated Press
This is actually a really good match up, I think if rocky did win it would be due more to how hard it was to hit him clean than anything else, Williams was a huge man with a chin of glass with the power and aggession of a bull, rocky would need to utiize his Bob and weave and superior boxing skills if he wants to win this, if he goes right at him and tries to slug williams it could easily go either way. I' give rocky the edge in skill Reflexes Chin Stamina And Bob and weave Williams has size Power And reach Rocky by t.k.o round 13