Ellis late TKO or UD. Ellis was a slippery heavyweight who had a sneaky great right hand and could crack for a dude who came from middleweight to heavyweight.
Ellis, assuming an American early 70s ref. He fits the profile of guys who beat Ruiz. Smaller, skilled, solid pop. Unless Ruiz's era's PEDs confer too much of an advantage (and if Ruiz uses them.)
That’s what I think too. Ellis could outbox Ruiz but John was durable so a knockout wouldn’t be as likely
I would rank Ellis around 65 and Ruiz between 70 and 75 of all time, possible higher than Douglas and Braddock. Ellis was sparring-partner of Clay in Louisville and might be quicker, but "The Quiet Man" weighted over 100Kg and seemed to be a bit more powerful (he stopped Oquendo, who had a decent defence/ chin, landed some bombs on Valujew, at least in their first fight in the second third part). So if a knockout happens, then will accomplish it likely the Boston Puerto Rican.
In all likelihood, yes. And, I doubt he would fight as cautiously as Roy did. When he learned how talentless Ruiz was, Ellis would likely turn up the heat without fear of significant reprisals from the oafish "Quiet Man."