I think he had the potential to beat a portion of the top heavyweight s going on in, up to the 60 s, and give the big gun s a nightmare Fight. Joe Louis, Jack Johnson and Marciano im referring to big guns.
Gene could beat a PORTION of the top Heavyweights in any eras included in this thread title. The big guns: I doubt it, not in their primes. Not very many of them anyway. IMHO, of course.
No, Marciano would have ground him down like beef and stopped him eventually. Ugly clash of styles. Prime Dempsey and Louis could pull something off with the right game plan. Liston struggles with his movement but eventually clips him and it's over. I could even see Terrel taking a decision. He was far from unbeatable even by olden day standards.
The short answer to that is yes. He would likely have lost to some of them, but he would have given them all fits.
Aside from the fact that he could box, punch and utilize the ring, the thing that made Tunney very dangerous was that he was a thinking fighter. Always coming up with strategies on possible future opponents. He was no automaton, he was going to have a gameplan and he had the tools. If he didn't beat the big guns, he would have let them know he was there.
Think I may have misworded my Opening post there a little, djanders. There's quite a few that, at his best, Gene wins. But the big names I mentioned, I don't see him beating but giving perhaps all of them a decent fight. Once we start moving in to the modern age and Ali, Frazier etc come in, I see Gene probably losing more fights.
Tunney would definitely get the worst of it at heavyweight. Maybe a Jack Sharkey on one of his flaky days would give Gene some hope.