I think Marciano grinds out a clear but hard fought decision.Toney would trouble Marciano, no doubt , and have him cut. But at 190, Toney can't sustain the activity level needed to hold off Marciano. A fight between Marciano and Toney might have been similar to Rocky's fight with Archie Moore, with Toney a bit more durable, younger and fresher than Arch, if maybe not quite as skilled and experienced.Jirov actually threw more punches than Toney did during their fight, but of course without the effect that Marciano's shots would have had.The point is that if Toney fights Rocky in the trenches like he did Jirov, he gets outworked.I doubt if Toney at 190 had the legs to keep Rocky at distance, and he sure didn't have the height and reach advantage many of Marciano's opponents did. Thats why Rocky wins a decision.
Rocky would have Toney looking for a weapon to protect himself with if he ever faced Marciano in the ring.