This is the worst possible style for Floyd to face. His defense would likely be good enough to let him survive until the later rounds, but eventually that right hand would find it's place and Floyd would get knocked out.
This thread sucks without the Hearns dies laughing before the opening bell and Mayweather is declared the peoples' champ option.
Hearns by KO in the 80 floyd would have stayed at 135 140 at the most.. Welters in the 80s where big, fast and skilled.