Early 1900’s ruleset: 5 oz gloves, No hand-wraps, Slightly heavier shoes, Very tolerable referee’s allowing a good deal of clinching, (Dirty clinch tactics) like bending, pulling back, and twisting arms are completely utilized as well as various forms of holding & hitting, Immediate action after successfully getting up off of a knockdown, Overall (quality of life) equipment is severely worse.
We can forget 1970's Muhammad Ali, he would have been gassed to fight 20 rounds. Peak 1967 Ali could have boxed 20 rounds, he had amazing stamina.
If Muhammad Ali had a certain period of adaptation to different rules, he would show why he is The Greatest. 1967 Ali would knock out Jack Johnson. 1967 Ali stamina is better than Johnson's; with the intensity of fighting as it was in 1910.
