Good example. 215 pound David Haye is the best example I think. I have no doubt Foreman would be just as powerful against big guys, but I doubt Frazier would be.
What is hayes knockout ratio from cruiser compared to heavyweight? What is his average weight differential compared to his opponents as a heavyweight?
I know Valuev was never stopped before, but had he ever been wobbled like that? Pity he never went down, people would not talk so negatively able up the fight.
Not sure about his KO ratio but I know for sure that he did what 245 lbs Vitali, 246 lbs Whyte, 249 lbs Pulev, 265 lbs Fury couldn't do: mop the floor with Chisora.
David Haye was 210 for both Harrison and Wlad. Frazier was 210 most fights and when he battered 245 lb Buster Mathis who was very mobile for his size. Joe intentionally came in lighter for Ali. Frazier would leave a pile of bodies behind him if he was around today.
Huck's another fighter who punches well above his weight. in fact most of the top cruiserweights would hold their own in punching power if fighting at heavyweight today. They just wouldn't necessarily win, due to the increased physicality of HW fighting today which favours the bigger man.
A example of a cruiserweight losing his power moving up is Holyfield. He was a power puncher at cruiserweight, but not at heavyweight. Frazier's KO rate falls dramatically as the weight of his opponent increase, probably the best example of KO's falling as opponents weight increases.
Haye's average weight at heavyweight is 214 pounds, and average opponent weight is 242 pounds, so 28 pound difference.