In a street fight he wrecks both, In a 60s-70s boxing ring, I believe they still had the free thumb so Jack Johnson could pull his shenanigans and frog march them around and clinch them to death. In his time it’s rough for GF imagine being hooked for 20rds when you can barely handle 4.
It depends on which rules they fight under. Old rules Johnson has a better chance. I think it might be a bridge too far in any case. He could last quite a while he was know as a defensive wizard. Never know these guys had exposure in later rounds as we know and sometimes ran out of gas. Old rules I like Johnson against Joe Louis. I think he could confound him maybe steal a decision.
I’d be curious to see how George’s stamina reacts to Johnson’s rough-housing and clinching style but I’ve read that apparently Wills and Kaufman were able to hold their own strength wise against Johnson so George and Sonny might just be a step too far to bully.