Lewis. I actually think the younger Fury who beat Wlad would have a better chance of confusing Lewis and potentially winning. But you need offense vs Lewis and i am not sure that Fury had enough offensive firepower. The older Fury who demolished Wilder 2 (arguably his peak performance) would have a punchers chance given Lewis could be hurt. (Let's not kid ourselves, McCall and Rahman aren't exactly Earnie Shavers). But i feel that this Fury was maybe too big and too hittable to survive Lewis. The tragedy of Tyson Fury is that we never saw him fulfill his potential. If he had dedicated himself between 2016-2019 and stayed in shape, he could have developed excellent offensive ability (like his right uppercut which he developed post 2019) combined with his mobility, footwork, feinting etc. His best fighting weight would likely be between 245-255 lbs. Perhaps this potential version of Fury (like a blend of the Fury that beat Wlad and the one who beat Wilder 2) could beat Lewis. But as it stands? Lewis by decision with Fury maybe surviving a couple of knockdowns. I do think Fury will stun Lewis at some point since both guys are so huge and hittable. Fury will have his moments. Lewis 8-4 UD with one or 2 knockdowns.
Despite Fury's antics, let's not kid ourselves. Dude was very talented. Manny Steward, Lewis's trainer, predicted years before Fury won the title that Fury had world class potential. Steward wasn't going to say such things just to be nice. He briefly worked with a young Fury and clearly saw what he was capable of.
Lennox Lewis would have to be favourite, but prime vs prime it would be close. Despite my intense dislike of Fury I have to acknowledge that at his best Fury would a very tricky opponent for any heavyweight-champion in history. However Mr Lewis is an elite ATG and he should be able to get the job done against Fury.
I agree Fury would give Lennox problems but I just think Lewis jab and firepower would prove the difference. Fury´s performances in the 1st and 2nd Wilder fights showed what he is capable of but Lewis at his best is not a one dimensional puncher like Wilder. Lewis chin will never be compared to Chuvalo´s but lets not forget Fury was decked by Pajkic, cruiserweight Cunningham,Ngannou+Wilder whilst Lewis survived punchers like Briggs (did get rocked in a mini-classic), old Tyson, Tua, Klitschko,Mercer,Bruno and Ruddock without going down. I´m not sure if Fury could say the same if he had faced those punchers.
Fury could absolutely whomp a crap version of Lewis. Best for best though I think I take Lewis, even though some versions of Fury would be a real handful for anybody.
Lewis by stoppage Fury has been able to get away with being floored numerous time by lesser fighters or lighter hitters but Lewis hits too hard and is too classy to let Fury off the hook. Fury in turn also doesn't have the power to maybe catch lightning in a bottle and stop Lewis with a single punch.
Back in 2020, in relation to this speculative contest, I stated that: "...it carries some intrigue, but I think I'd want to see Fury battle-tested against a few other of the top-end opponents, before making assured claims about versatility, accuracy and speed, compared with Lewis." I have to say that, other than his recuperative powers, I've not seen anything more from Fury since Wilder II, that has demonstrated he'd have an advantage of any kind over Lewis. Moreover, Fury simply doesn't have the offensive output to concern Lewis at all. How long it lasts depends on how awkward Fury can make it, if he can succeed in making it awkward at all against Lewis. If he can't, I can see this being not greatly different from Lewis/Grant (two or three more rounds, perhaps), with Lewis winning this and doing so with extreme menace.