I will go with Sonny Liston, but I am not real confident. I am thinking this could be a 4-3 thing in a best of 7.
The type of fight you could probably get very juicy odds on Wills. Liston will deservedly start favourite but put some coin down on the dark horse.
I'm picking Wills but I'm not so confident as there is really no footage of him in his prime. I'm picking him based on the quality of his opposition. He did have a stiff jab, a solid right, decent inside game and a good chin by all accounts. I think he could outbox Liston for 15 rounds.
Liston mid-late rounds by TKO and Wills would do better than Cleveland Williams, It would be like DeJohn fight.