Ira Berkow, 'Counter Punch' (May, 2014) Section V. The Manassa Mauler 'Peachy Caveman' (Feb. 1970) p. 76 Mr. Dempsey was asked how he would fight Joe Frazier, who has a crouching style. "Gotta get the man up," said Mr. Dempsey. He did not raise his right arm off the arm rest, but he made a quick fist and gave an upward snap of his wrist.
I think that Dempsey would slaughter Frazier in one or two rounds. He was more versatile, more mobile, had a better chin, and he hit harder with both hands.
I would lean towards Frazier stopping Dempsey after 10...Would also take Frazier over Marciano. I think Frazier would be capable of pushing both onto the back foot...taking away some of the leverage on their shots. Brutal fights though...