It's a gloved match, but it's under the Queensbury ruleset of the 1880s. Unlimited rounds, smaller gloves and I'm sure there's a few other aspects about the rules back then that are different. Does Sullivan stand a chance?
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 Sullivan within 15 rounds.
Given how capable a grappler Ali was under the rules he fought under, I'd expect he'd do well after a period of adaptation to the rules of the era. The guys I'd worry about being sent to fight Sullivan would be guys who were never good grapplers.
It all depends on if Ali is able to learn and adapt his style to Sullivan's ruleset, something we have no way of knowing. Ok that's not entirely true. It also depends on how good Sullivan is, also something else we don't have a clear way of knowing. So who wins? You'd have an easier time finding the meaning of life. I'll take 42 by UD.
In 1880's I'd take Sullivan to beat Ali's brains out. Matches in those days were closer to street fights , grappling, wrestling and fouling and John L. was well versed in that. Remember when Ali jumped up and grabbed Frazier in the studio with Cossell watching the replay of their fight? Years later Ali admitted he was scared because Frazier could street fight and he could have broken my jaw.
The idea would be to give Ali a while to learn the rules of the day. Anyway, the reasons you list are why I always pick John L in the "have one guy with you in a bar fight" scenario. John L would be an absolute beast in a situation like that.
Ali destroys him. A guy who couldn't beat Corbett is not going to last a minute with Ali and is not going to even get a chance to "grapple."
That is like saying that a guy who couldn't beat Leon Spinks, is not going to last a minute with Sullivan. It is a total non argument.
If it's M of Q Ali easily ... kind of like how Tyson will beat Ngannou ... if bareknuckle another sport all together ..
Based on the fact that all of the early heavyweight champions that there is film of look clumsy and awful. I have no reason to believe Sullivan was any better.