If Foster had being around in the Johnson era and Jack had accepted a challenge from him? I's it another failed attempt by Foster?, or maybe he gets lucky against a over confident JJ? Johnson of the Ketchel fight here.
Thing is, Foster in Johnson's era wouldn't have the style he did. But assuming he somehow did, I can't see him winning. He didn't really do anything at heavyweight, though granted his opposition was elite. But still, Johnson is significantly more proven and a real heavyweight. I've got to go for Johnson, and honestly I don't think Foster has a puncher's chance either.
No your right, he more than likely doesn't have the same style. If he's one of the talented, avoided guys of the time, then would be interesting to see how Foster copes. He d be fighting smaller heavy s but no less hard or tough than Joe Frazier. So against Johnson, he more than likely getting beaten up over the course of the fight imo. He may shake up Jack but Johnson takes the ko win. Johnson by 12 ko.
If Foster fights in his own style versus Johnson, Foster will KO Jack with relative ease. Johnson was highly overrated when compared to fighters outside of his respective era.
Foster entered the ring under 190 pounds for all of his HW fights. If the version of Johnson who beat Ketchel at 205 pounds shows up, I like Foster's odds. Foster also fought way better opposition despite falling short at HW.