If Big John L gets the gloves on and fights any Heavy weight champ from history, and in their time and rules, who's the best he whips?
There's practically no way to assess what Sullivan would look like in a modern gloved boxing era other than his roughness , power and his willingness to fight. Trained properly I think there's some guys he could get outta there but it's sheer unsupported speculation
**** off White Bomber. You wander round this forum like a simpleton repeating endlessly that [more modern fighter] will beat [less modern fighter] "easily", over and over and over again, contributing literally zero analysis, and in causing upset to people on the forum who are making minor or major contributions, actually achieving net - zero as an overall contribution. You're a literal waste of bandwidth, fanny.
Sullivan was likely no better than the likes of Roy Shaw, Lenny McClean or Joe Savage. He may have been a decent bar room brawler/street fighter in the 1890s but doubt his skills (or lack of) would stand him in very good stead against highly trained skilled athletes from 50-100 yrs in the future
I hate to be a wet blanket, but there's no way to know. I've never seen an elite fighter with old timey bareknuckle-derived skills fighting a modern one. I've also never seen Sullivan in a fight. We have pictures and snippets of Old Sullivan film that paint (IMO) a consistent portrait of the man's style. But judging from the fact that @janitor strongly disagrees with me on interpreting that evidence (and we are among the small number who even care about it), I doubt that the evidence is all that clear. Who's the best Sullivan could beat? I don't know, and I don't think anybody else does, either. Maybe you could pick Corbett or Fitzsimmons, just because they're close enough contemporaries that you're somewhat comparing apples and apples as far as evidence goes.
I know, it's frustrating really. But we have bit s and bobs of knowledge about the Boston Strong boy I suppose.