Re: Holmes (early 80s) vs. Ali (late 60s)
Ali has just proved so much. His superior mobility and speed let me think he outpoints Holmes in a prime vs prime matchup. Both have terrific recuperative power, but Ali has an edge in strategy and on a mental & thinkers aspect too. Ali has has the slightly better chin to combat Holmes' superior power.
I also think a prime Ali from 66-67 threw more punches and had better stamina. Ali's stamina and punch output in his prime are quite underrated. Anther reason why I see a prime Ali beating a FOTC Frazier (I know that's not related, just a side point).