Liston by a knockout. I see Sonny`s jab actually grinding Tommy down by the mid rounds and the follow up being almost a forgone conclusion. Sonny Liston wasn't unbeatable as we know but he lost his title to the greatest heavyweight of all time. It was the way he lost that hurts him the most. With that said just about any other heavyweight in history would have lost his title to Clay/Ali at that time.
Sonny Liston by KO 5, Tommy Morrison would have his moments, but it does not matter who you fight, you can only fight what is in front of you. Boxing was not invented in the era of the Steroid Bunch. This is the Classic Forum, not The General Forum.