I would fancy Morrison a little more than some people hmm... Morrison had huge power and even a decent chin (I use the term 'decent' quite loosely), he just gassed after the 3rd round consistently. So if we're talking about Liston any time after 1966, Morrison might surprise him.
Sonny Liston gives him a beating that makes Tommy pray for Mercer to come back and be all gentle with him again.
ROUND 1: Liston bullies the **** out of Morrison with the long battering ram jab then KO's him with a brutal straight that violently snaps Tommy's neck back. It would be highlighted and replayed several times for dramatic effect.
I always had respect for Morrisons career , especially that gorgeous Left hook of his . BUT i think Sonny would have been too much for him and would have caught up to him eventually . Morrison would have taken advantage of Listons slowness and bank some early rounds . But after 6 , 7 rnds i see Liston catching him with a combo and finishing him off against the ropes .
Sonny wins this as Tommy would be intimidated throw too many punches and be wide open Ray Mercer on the other hand demolishes Liston just like he did Morrison