It would depend on whether Mick was still alive, and if Adrian was ringside. If so, Balboa could do a ropa-dope number, take 400 head shots, whilst exhausting Tyson. Of couse, he'd have to protect his ears. I'd imagine that they'd simultaneously score a knockdown on each other, with Balboa clambering to his feet just before the ten count, leaving Tyson gibbering something about pigeons and Allah on the canvas. After the fight Steve "Crocodile" Fitch and Don King would have gay sex, and Tyson would french kiss Mr T.
p.s. Carl Weathers (Apollo)- to my mind he had a perfect physique. Must have put some serious effort into his diet and training. He was in Predator, but I don't know how he didn't get more roles in top films, or even leads.