This would actually be competitive. Marciano had trouble with Jersey Joe Walcott, Ezzard Charles(particularly the second fight) and some trouble early with Archie Moore. Toney I feel was every bit as slick as those guys and was quite durable(big heavyweights failed to knock him out past his prime....plus Toney emulated these guys as he has said in the past) I feel he could hang in the pocket with Rocky and bang with him. He might be out worked the way Charles was in their first fight and could very well be finished by a shot the likes of which Walcott was taken out with in the first fight. Realistically though if Toney was stopped it'd be by getting worn down because his chin is granite and has held up against men far bigger naturally than Rocky. I just don't see Rocky running through Toney. He'd have to adjust like he did in the first Charles fight to bring the pain and avoid Toney's wiley counter-punching
Marciano would eventually wear him down,Toney gets lazy at times and that would be when Rocky does his damage most,although I can see Toney landing at will in spurts. Rock would stop him in 12 I dont think Toney can hang with the Rocks pace and eventually those big shots will take its toll and marciano would finish him,with the fight about even in the 12th. Both will take a lot of punishment with rockys face beaten up,but Toney ready to fall the ref saves him or maybe he goes down and gets up but the fight gets stopped.
I'm one who knows better than that so don't count me in that statement. Lights Out versus The Brockton Blockbuster would be a hell of a barnburner and would be at cruiser nowadays. Rocky is much more Toney's size.