1. 45 rounds, gloved? 2. Street fight, no rules? Who ya got? Personally I see Sullivan winning the gloved fight, probably by KO. The street fight is a tough one - I've heard reports about both men being very tough dudes outside of the ring.
In a gloved fight I would lean quite heavily towards Sullivan. While both were concusive punchers, Sullivan apears to have been far and away the better finisher. As for the street fight, it is hard to say. Both were prety useful, but there is not much by way of a frame to compare them.
In Pollack's Jeffries book he recounts that in 1905, at the age of 47 and weighing 270+ pounds, John L. Sullivan KO'd Jim McCormick in the 2nd, leaving him unconscious for 5 minutes... the same McCormick that went 7 rounds with Johnson and 8 with Ruhlin and KO'd Kid McCoy in 1. I have the gut feeling that we are all underestimating just how good John L was and how much power he carried. He seems to be in another class than Sharkey, in any arena.
Two tough guys locking horns, i would say gloved bout would be Sullivan win, but in streetfight Sharkey was tough as teak and in a no holds bar fight, i say Sharkey is the victor. The streetfight area would be a bloodbath for sure.
.. Young John L. This content is protected Getting paunchy, below. This content is protected [ame]http://www.youtube.com/watch?v=GeNUufI4nN4[/ame]
Sharkey to me fought and beat much better fighters in the ring, and also has many early stoppages. But we are talking a street fight here where there are no rules, and that tips the odds to Sharkey who didn't mind breaking them.
Sharkey was stopped 4 times whilst still in his 20's , twice by one punch ko's. Sullivan was only stopped when he was a mere facsimile of the fighter he had been, Sullivan was a dissipated 34 years old ,with only 3 rds of ring action in the previous 5 years. It still took Corbett 21 rds to accomplish the feat. I think Sullivan also had better one punch power, than Sharkey. I pick John L under any circumstances.