Norton takes it around the sixth or seventh. Floyd would have his moments,definitely but he's not strong enough to beat Ken.
Norton. Stoppage. His left hook was a stinger and was fast too. Floyd was fast but Norton wasn't far behind. Patterson wouldn't like the taste off that hook. And the piston jab neither.
Not a lot of 'era' difference here but a little. #1: Norton was far behind Floyd in speed. #2: You're comparing Norton's left hook to Floyd's Granted both showed a weakness to power when faced with overwhelming size differences but Floyd was 190 and Kenny was 215-220. Did Foreman or Shavers hit Norton any harder than Ingo's bomb or Sonny's onslaught?? We'll forget about Cooney's massacre of Ken, Floyd was the same age at the time and was giving Ali hell! It's all styles and eras. Had Floyd been born 10 years later, he would have had Norton for lunch!
Patterson wasn't a big eater but he probably would have eaten Kenny over a slow diner. Maybe a few burps on the way. Seriously the missing factors here are that Norton never met a swarmer as good as Patterson and Floyd never beat a decent Heavyweight the size of Kenny.