Tunney would stay disciplined and focused to move, move, and move some more, while accurately landing with both hands. It would be a conservative performance by Tunney, but he would keep it up and would hurt and possibly stop Cooney in a late round. Because he didn't have the power of Michael Spinks, he wouldn't end it as quickly as did Spinks did against Cooney, but overall, Tunney was better than Spinks in every other way, and would outclass the big guy all the way.
Honestly I would favour Tunney and wouldn't be surprised if that right hand managed to find Cooney's temple and make him do the chicken dance. When Gene wasn't slapping and planted his feet he seemed to pack a decent punch, when Cooney's stamina begins to falter after chasing Tunney I can see Gene getting more aggressive and getting a TKO late.
Ive often felt Tunney is the most 'historically' alike to Usyk, well, him and Schmelling. Cerebral heavyweights who could formulate and box to a plan but pack a punch when they plant their feet. Cooney might have prodigious power but he won't find a home for it here. Tunney by late stoppage.
Cooney knocks his Bernard Shaw reading noggin into orbit. KO4. Tunney looks fast and nimble because we only have film of him versus late stagers past their pull dates or a lumbering oaf Kiwi. No fast twitchers, no swivel hips, no athletes.
Stylistically, Tunney should be favored, but I'm not sure if he'd overcome the size and power difference. Cooney did manage to beat the cagey and quick Young, who might be a decent stand in for Tunney. But then again, Spinx did a number on a (past it) Cooney and he was only marginally bigger than Tunney (both were light heavies with smaller frames moving up). Visualizing this fight in my head, I see Tunney using lateral movement throwing sharp jabs and straights to the head and body never staying in one place for long, while Cooney invests in some thumping body shots. At some point, Cooney will threw one of his powerful hooks to the head, and at some point he'll connect. His height, reach, and timing will make up for any speed differences eventually, and it'll be a question of if Tunney can A) get up and B) survive. Cooney could be a pretty vicious finisher and he's got a significant 30+ lbs advantage behind those hellacious hooks, so idk. I think Tunney could survive the round, but does he survive the fight? If Cooney cracks and drops him a 2nd time, that's probably the end of the match. However, Cooney wasn't the most durable guy either so it's no guarantee Tunney's solid right hands don't chip away at the Big Man's endurance.
For a supposedly bright guy who aspired to be more than a pugilist his racist views seem incongruous. Before anyone jumps in that has squat to do with how good a fighter he was or wasn't.
Tunney was the far better boxer but Cooney has a live punchers chance. A past prime Dempsey put Tunney on the deck for a controversial long count. And the size and reach difference here would be significant. Ring size might also play a part