1. Foreman - without a shadow of a doubt. Was in tremendous shape for this one. You have to be to absorb that kind of body shots. His lead right hand snapped Foreman's head back viciously. The combination punching was exceptional. 2. Bugner 1 - some will disagree. Obviously beating Bugner is not as impressive as beating Frazier of Norton. But in terms of how good he looked, how quick his feet and hands looked, how good his left hook was, how well he fought off the front foot - i rate this super high. 3. Frazier 2 - he had Joe hurt in round 2. He looked great. Smart boxing.
Surprised you don't have Norton 2 for me that was Ali at his sharpest in the 70s IMO. Ali had the constant movement, sharp with punches, good stamina. For me I'd say.... Norton 2 Foreman Quarry 2 Ali held too much for my liking in the 2nd Frazier fight so I don't rate that quite as highly.
In regards to performances I felt he looked his most aggressive against Bob Foster in 1972. He was in his best condition physically in his rematches with Norton in 1973 and Frazier in 1974 he needed to rectify the losses and trained harder than he had ever done previously in his career similarly with his rematch against Spinks in 1978 he sparred and ran more than he had in years although his skills had eroded at that point. My picks are Foster (1972) Norton 2 (1973) Frazier 2 (1974)
He almost looked like the younger dancing Ali in fight after the 1st Frazier fight against Jimmy Ellis. He was the heavier stronger Ali at 220 but was still a young man and showed flashes of his old speed and elan. Was like he finally knocked all the rust off.
He really toughed it out against Oscar Bonavena in his next fight after that. It's also quite an underated performance.