BoxRec

Presumably Ali knows that he is fighting twenty five rounds against a tough guy with good stamina so he'll train and pace himself expecting a twenty five round fight. While it is a big increase over fifteen boxers could do it in the past, so I don't think Ali would have much trouble adapting. Given the rather primitive style of Jeffries and his poor performance against boxers like Fitzsimmons and Corbett I think Ali wins on points as I don't think Jefferies is going to KO Ali and I don't think that he can win on points.