Comeback version of Foreman was slower and threw straighter punches giving Frazier a chance to slip some of those shots and come up with big punches himself. His work rate and stamina would also be a big factor in this scenario. I pick prime Frazier to beat 40’s George. Not sure exactly how it ends though.
Comeback Foreman would still overpower Frazier he was stronger at 260 but more patient. Foreman still shoved fighters on the shoulders throwing them backwards only he was larger and smarter about timing fighters, Frazier was not real hard to hit and his bobbing and weaving style was because he was short, nearsighted and strong....his issue with Foreman was that he was a swarming puncher but Foreman was a much bigger, stronger and harder puncher.
I still pick Foreman if it's 38-42 year old Foreman. It just goes more rounds than it did in 1973. Resembles more of the 1977 fight.
Prime Frazier wins IF he applies the right tactics. Like he did in the second Foreman fight in real life. But in reality that requires him the get beaten first and then make the right adjustments.
Comeback George was as slow as molasses. I actually think a prime and that much faster Frazier’s best chance would be to get in there to mete out as much damage as possible early. It was earlier in his comeback and Foreman did come in that much lighter (235 lb?) than what he later averaged out to but Qawi had notable success catching George flush quite a few times. I think it’s reasonable to conclude, all in all, that prime Frazier does so much better than a bloated Qawi did - against an even heavier and slower Foreman.