I think it more likely that he was telling the truth-except for the 1/10th comment. Many do not know the basics of mathematics such as force & statistics, no man can hit 10X as hard as even an average man. If Sullivan hit, say, 20% harder than him or the #2 guy, that would be massive.
I’d bet my house on the 46 year old obese alcoholic Sullivan that KO’d McCormick to take Galento’s head off, let alone peak Sullivan. I don’t need film, Sullivan showed more ‘science’ in the few seconds of shadow boxing with Corbett than I’ve ever seen from Galento. He can’t possibly be worse.