I just see Marciano making the mistake of coming forward too much. But Tyson would drop him in the first round imo. If Walcott could find a bomb to drop a young Marciano, Tyson's combinations are bound to produce a knockdown in the first round. I can't see Marciano stylistically finding a way to win this. I see this fight looking a whole lot like Patterson's two fights with Liston. Because after the first knockdown Marciano would keep getting up, I think he wouldn't be KO'd, but once Tyson sees he can be hurt he will throw everything at him to get him out in the first round and I don't think Marciano can weather that storm.
It's all Tyson and early for me. There's just nothing that Marciano can do to stop Tyson early, but plenty in favour of Tyson stopping him early.
I have seen posters opine Rocky can beat George Foreman and Lennox Lewis who are both much bigger than Mike and generally higher ranked. In other sports I have seen posters opine that Bill Russell would be as dominant in this era as he was in his own.
Walcott might make it a few rounds being slick before being Ko'ed, Moore goes out early against Tyson's firepower.