Michael Spinks definitely had the power in his left hook to knock over Moorer with that chin of his.

Both 6'2", and both with KO power at Light-Heavy. Moorer with more power, and a devastating short hitter.
Spinks showed a better chin and more versatility, and more consistency.
Moorer ran hot-and-cold.

I'd go with the Olympic Gold Medal winner, Michael Spinks in this one..