The Lyle fight should give you some pause for thought. Jeffries probably didn't hit as hard as Lyle, but he was probably a better counterpuncher, and certainly a lot more durable.
And if Lyle fought Corbett, Sharkey and Fitz as his greatest challenges, we would be talking about him as the greatest puncher and iron man the sport has ever witnessed.
The lyle fight leads me to believe louis and tyson beat george. But not james, guy is overmatched. His durability is questionable considering his opposition.
Fitz never beat a world class man over 200lbs. Look it up. He beat three fat lumps of no class at all. Sharkey only beat one man of 200lbs, 205lbs Fred Russell and he was 11-5-2 at the time. Corbett beat two men over 200lbs a totally washed up ,bloated ,booze ridden, 36years old Sullivan ,and a 201lbs Kilrain in a 6 rounder. If there were plenty of big fighters in Jeffries era , how come he never faced them?
Foreman was stronger than Jeffries, had an iron chin, the power would be more than Jeffries could handle, he couldn't move Foreman around, if he got into range of Foreman, it's lights out for Jeffries,,Foreman takes him out in 1 round.
It would be interesting depending on the approach Jeffries took. A lot of observers felt Jeffries was a bigger version of Tommy Ryan when he was countering instead of being aggressive. George is a murderous puncher but he can afford to get reckless like many aggressors tend to do, even on the film we have of him Jeffries was quick to counter when his opponents led. That being said, he always got hit even in fights where his defense was universally praised. Jeffries also never tasted the power of a heavyweight puncher like George, especially in repetition. Foreman will land and probably land in combinations. Jeffries certainly isn’t getting an early finish even the most idealistic interpretation of the fight in his favour, so he will have to weather some of that rain from the storm and we just don’t know if he could.