I'd give Carlos a decent chance. He was physically very strong and relentless and could take bombs without blinking. His frame and height, 5'11, were such that he probably could back on 10 pounds or so without issue. Of course, Carlos would be well-advised to quit smoking for this fight, because he'd after take Bob into deep water and withstand heavy artillery the whole time.
Thing is Monzon relleid on his size a little bit to make things happen for him, no? Now that's stripped away, I don't know. He could fight Foster for sure, but I think Foster would take it. He sure wouldn't be my choice out of all MW's. I think, like some of these other guys, i'd go for Hopkins. But I'm surprised no-one's offered up Jones. Don't you think he'd have a chance at peak?
As opposed to who? You see what i'm saying, who is there that's been up to LHW from MW that would have a chance with Foster?
Dick Tiger. Oh... I don't favour any middleweight over Foster - his power and size would come as a massive shock to even the toughest like Hagler and Monzon. Come-forward fighters with average power like Fullmer and LaMotta would suffer the most convincing losses. Standing a better chance would be technicians like Giardello or Griffith who might do a half decent job of avoiding Foster's titanic lefts and rights, but ultimately they'd succumb to his rangy jab and skills anyway and lose lop-sided decisions. Performing best would be the ones with the best balance durability and skill; Hagler, Monzon, Robinson, Hopkins. But I wouldn't give any of them more than a 20% chance of winning against a primed, lean, nasty Bob Foster.
I think that PEAK Dick Tiger has a better chance than most (though i'd favour Foster). He has some decent wins at LHW, admitidly at a time where the rest of the American fighters wanted to fight for the US title Foster was so far ahead. All i'll say is Foster fought literally the worst fighter Tiger ever was. Literally.
You make it sound like Tiger was completely finished. He was still a good fighter - a very good fighter. Tiger was coming off a win over Roger Rouse where he didn't take much punishment and looked quite devastating (great knockout), and would later beat Nino Benvenuti as well as two other light heavyweight contenders. Tiger was nowhere near finished; Foster was just too good. Too tall, too rangy, too powerful. Tiger rarely got close, and when he did, he couldn't do anything because Foster would smother him. A peak light heavyweight Tiger came when... '66? Two years before facing Foster? Tiger's engine was still revving in '68 and would continue to do so after he lost his title. You can say all you want about Tiger suffering mentally or whatever in the build up to this fight, but I've seen the Rouse fight and he looked no different. Foster was just much, much more powerful than Rouse and a far more intimidating prospect; he could back Tiger up with just his sheer physical stature and threat of his vaunted dynamite.