There's a video on youtube of Tyson being measured on camera and he was just about 5'10 in the 80's if I recall correctly.
I think the first few rounds would be more interesting than people think. Tyson was confused and looked out of his depth when Mathis Jr kept stepping into his range and worked on the inside. For 99% of his career, Tyson always had to be the one to step in and find a way to get past the taller guy's jab to land punches of his won due to his short arms. Not only that, but Tyson needed room to use his trademark head movement to built momentum and speed for his explosive combinations. I think Frazier's non stop forward momentum might smother Tyson before he could really use his head movement or wind up those looping bombs he was known for. As a result, Tyson would only be able to hit with maybe 50% of his full strength and uncomfortable with the pace Frazier would be setting while Frazier would feel right at home. In addition, Tyson wasn't used to someone daring to go to the body and initiate the offense. For at least 1-2 rounds I think it would be a very ugly phone booth mugging with lots of shoulder to shoulder inside fighting and not too many solid blows landed. Yes Tyson was a fast starter, but if Frazier steps right into the eye of the storm, how much damage would Tyson really be able to dish out? It could get really dicey if Tyson can't adjust to Frazier's smothering and attempts to drag him into deep waters.
I always thought Mike was quicker than Frazier and more two handed and would take him out in a few rounds..
