Foreman Ko in 4 rounds, Tyson would start aggressive and come at Foreman which is what Foreman would like, Foreman didn't like having to go look for his opponent, he wouldn't have to go looking for Tyson, Tyson would be trying to get up close and Foreman would be nailing him with uppercuts at mid rang and controlling him with the jab and drop him a few times before it is waved off
If he fought 70s Foreman, KO'd within 5. If he fought 90s Foreman, KO'd within 10. If Tyson fought this one smart and didn't gas himself, he could win the decision.
I would go for Foreman by mid round KO but woudln't bet big on it, i'd by no means rule out a Tyson stoppage either.