This question does not have to be strictly so. The real question is which Muhammad Ali would win. Peak Ali of the first career, or peak Ali of the second career. So feel free to take versions of Muhammad Ali beating Frazier 2, 3 or whatever you see fit. Muhammad Ali of the second career does not know how Muhammad Ali of the first career thought. Or if that's easier for you - it's about two different people. I hope I explained it well.
Zaire Ali. He's smarter than 1967 Ali and unlike 1967 Ali, he would have the advantage of knowing what his mind was like back in the day. He would know everything the younger one was planning, and advantage the younger Ali doesn't have.
It's still a tough fight to call, we know both Alis struggle with good technical boxers with quick hands and a good jab (Doug Jones, Ken Norton). Zaire Ali is a better technical boxer than 60s Ali, and was bigger and stronger. I don't think he would fall for the younger Ali's tricks
1967 Muhammad Ali by a points win. Both are not knockout punchers, one has speed, stamina, reflexes and terrific footwork. The 1974 version of Ali has already had his jaw broken, did not like to train, lacked stamina, had weight that fluctuated, did not have the stress of never being able to fight again like the 1967 version of Ali had during the turbulent 1960's during Vietnam and Civil Rights.
My opinion no heavyweight in history beat Ali from 1966-1968 , he had matured physically and was at his physical peak, and he had matured mentally from where he was from 1961-65". Not even Ali from the Zaire fight beat that version of him. But I'd give my 30 yrs in law enforcement pension (Not really lol) for the pre-fight press conference!!! That probably would be more entertaining than the fight itself.
1967 takes a points verdict by around 9 - 6 in rounds. 1974 Ali is as fast as 1967 but only in flurries whereas the younger Muhammad can keep it up all night.
1974 doesn't have 67's pure one punch handspeed or combination punching fluidity. He plants more and hits harder with the straight right and right lead but to my eye, 1967 has headmovement and that double right hand lead that he took Folley out with that the 74 version doesn't do as smoothly.
I think we’re gonna need two Dundees and two Bundini Browns for this also. I don’t know if the space/time continuum can handle all this without something cracking or blowing up. If the Universe remains stable, I’ll go with the 67 model of Ali also. Boxing IQ is on a needs basis - the young Ali’s boxing IQ was in perfect complement to the young Ali’s physical abilities.
Too bad that we did not get a chance to see Muhammad Ali in his prime years that would have been from 1967-1970. Ali was at his fighting peak from 1964-1967, he was inactive in 1968, 1969 and the early into late 1970, we can only imagine.