Williams could win this one, but Quarry had a very good left hook. Not as powerful as the Mike's who stopped Williams, Weaver and Tyson, but a good solid left hook, which Williams was vulnerable to. Outside of that, I do think Williams was approximately as good as Ellis. So I slightly favor a prime Williams.
Carl Williams had everything that you need to be a great, or very good, fighter. He also had a habit that undid it for him; when he threw a left handed punch, he dropped his right hand to his hip. His jab and reach would trouble Quarry and it may be enough to win him the fight. Maybe on points, maybe by causing some facial damage. If he was smart he would box a disciplined fight and keep that distance, not look for a ko and box smart. But it would not be above Quarry, in an attempt to make Williams come to him, act like he was hurt and go to the ropes. And Williams would follow him and start to open up and get hit flush with a hook when he dropped his right hand. And probably a right hand behind it. If Williams took that well and went back to boxing he would probably win. If it hurt him and he started to fight, he would get countered more and probably stopped.
I like both of these fighters I would favor the The Truth here. He's got the height, range and jab to keep it his way. Williams jab would probably cut Jerry. Williams TKO mid rounds due to cuts.