Its tough to say because Kenny's style was very awkward. The key to Norton winning would be if he can get close enough to Vitali to land some of those over hand rights. I think with his speed and conditioning he probably could. However I think Norton has a better chance of beating Wlad then Vitali based on the H2H differences.
Vitali would demolish Norton. North had a terrible chin and couldn't take a punch. He'd have huge problems with Vitali's defensive and counter style. Honestly I don't see Norton landing much in the early rounds and once Vitali lands a few simple bombs from the outside Norton would hit the floor. He'd get up a couple times and until the ref takes him out.
Norton had no chin fightin in a era of small HWs . A 250 lbs vitali would absolutely brutally destroy him ala Cooney blasting him out in a flash. most the guys Norton fought barely weighed 200 lbs and a lot of them weighed less than 200.
I see prime Vitali's power massively underrated here. Of course if he connect early he could tko/ko Norton. That said, no particular wonder if Norton somehow manages to outpoint Klitschko.
You can't boil it all down to the weight and height.. Norton had a fragile glass mandible, but style wise i think Vitali would struggle with him.. I think Vitali would struggle to land his power shots on Norton to finish him, Norton would walk down and hit Vitali down the stretch..
Norton would need to change his style vs Vitali. Norton proved he couldn't win shootouts against big punching heavyweights. I dont see Norton winning this fight.