Bigger HW Title fight?

[Dark Lord Al]

Tyson V Spinks , two unbeaten fighters .
Neither dodged the draft either.

By your definition you are choosing a light heavyweight blown away in 91 seconds by a rapist as the biggest heavyweight title fight.

Spinks had beaten the long reigning champ in Holmes.
In 1988 Tyson hadn't committed rape at that point , although some people would argue that after the 91 seconds ,he had.