Patterson gave Chuvalo consistent trouble for 12 rounds and won what was FOTY in 1965. But the star of the show here is both mens endurance and defense. I bring this up because- Morrison I think would fade quickly in the middle rounds and Chuvalo would pick him off. Morrison doesn't have the sort of defense needed to keep safe from Chuvalo once he [Morrison] starts getting tired I see Chuvalo landing strong right hands, I think Morrison is exhausted and can't get off the canvas by the 8th round.
George Chuvalo is more durable but lets me not forget what Joe Frazier did and took him out on a TKO with his left hook. Tommy Morrison had a decent left hook too but I think Chuvalo would likely survive and take him in the later rounds ala Ray Mercer but maybe not in such sensational fashion.