On Sept 21 1955, Floyd Patterson fills in for an injured Archie Moore.

That's pretty much how I see it. I think any version of the Rock is a bad match for any version of Patterson, even though I am a huge fan of both. Floyd's best chance would be to make full use of his speed and not get drawn into a shootout. Otherwise the bout would quickly resemble the Liston fights and the first Ingo bout.

 

Did Cus ever give his thoughts on how a Patterson Marciano bout would go?

 

Marciano gets up from the canvas once in the 2nd round and then catches Patterson on the inside hurting him. Patterson crumbles to the floor, but he also gets up and
then uses his speed to keep Marciano off of him to end the round. Marciano ends the fight soon after as Floyd just cannot match his power and chin and cannot keep him off for long with just his speed.

Patterson would probably get KO'ed faster than Moore did. Floyd would try throw punches leaving him open for counters, and he did not have as good a defense the "ole Mongoose had" .

 

I think it's a very tough fight for Patterson. He had the physical capacity to beat Rocky but his style would make it almost impossible to last 15 rounds.