Re: Durelle - How hard could he hit?
I believe it was around the time of the Scypion/Classen tragedy that Jack Sharkey discussed how the decision for a referee to stop a match could be a difficult judgement to make, using Moore/Durelle I as his example. (He may have been making reference to Owen/Pintor, or Hart/Denny, but it was after some such event during that era.) In any event, Sharkey's refereeing career did not have the hallmarks of a fatality waiting to happen, as Ruby Goldstein's did (especially after Johansson/Patterson I).
A quick check of Moore's record indicates that in 220 matches, he was never stopped at the referee's discretion. (Boxwreck.com lists his loss to the phenomenal Eddie Booker as a TKO, but my Ring Record Book simply lists it as a clean kayo.) The three knockdown rule was in effect for his match with young Cassius Clay, but in all his other stoppage defeats, he was apparently floored for the count. He certainly never suffered any apparent neurological deficits from his lengthy career, and he functioned extremely well to a ripe old age.