Who had the best cardio or stamina in each weight class in boxing history?

Fury & Joyce have special stamina for 270 pound men

 

Hard to say Pacman @ 147, I find that impossible since he was old and fat lol.
Surely there are many with better stamina than him

 

Mate you've just gone against ya own argument you mentioned how many punches he threw and then said it doesnt matter how many punches he threw ?? What's ya point you actually trying to make

 

Don't ever recall seeing Mayweather breathing heavy lol but people obviously won't want to give him any type of credit

 

My point is you're an idiot and now I'm blocking you. Good bye.

 

We not talking about his prime talking about him as a welterweight

Wow get a grip mate clearly to immature for a adult conversation

 

That's raw efficiency not raw stamina.

 

Hard to tell in each weight class, but the obvious pick for the boxer with the best stamina ever pound for pound and in heavyweight is the one and only Rocky Marciano.
Rocky Marciano could punch constantly with full force on every single punch until the last round. He ran a ton , trained harder than anyone in the history and never took a day off.
If not a boxer he would have been a marathon runner