I saw these guys a great deal on the old Gillette fights and I will go against the grain, I imagine, by picking Fullmer. I wouldn't put any money on it, but I think he would bull Griffith around and has a lot more speed than Tiger did to trap Griffith along the ropes.
We all know about Fullmer....grind'em out, rough & tough style. Griffith is hard to judge. Pre-Paret he was very aggressive, afterwards he changed his style. Hurricane Carter flattened him in one round ("No welter in the world, belongs in the ring with me"). But later on, Griffith moves up and beats Tiger, and later was competitive against Monzon. The Fullmer who beat SSR and Basilio up to year 1961 probably outpoints Griffith. Afterwards, Griffith is too mobile for him.
I'm a big fan and admirer of Gene Fullmer. He did great within his limitations and was so underrated, but Griffith takes this one. Emile Griffith settled into a style that made him the great mechanic that he was. He could adapt to just about everyone and it took the true greats to really take him. I think he outpoints Gene in 15 if it was for the title. He would have outboxed Gene sufficiently to take the decision.
