Obviously Marciano & Hagler will get mentioned, and rightfully so. Take those two out of the picture, and who do you rate as having an unreal gas tank? Calzaghe was a freak. Manny was out of this world. Juan Diaz has arguably the best cardio I have seen in a Boxer. GGG deserves a mention. He never stops moving or throwing. Your turn...
Salvador Sanchez. Never saw Chava breathe hard, or even through his mouth. Fighting Harada was a whirlwind for 15 rounds. Jung Koo Chang also, with constant feints, swarming and clever boxing. Khaosai Galaxy could slug you at any time. So could Sung Kil Moon. Archie Moore was as strong as a bull, and had amazing recuperative powers. Henry Armstrong, for obvious reasons. Vicente Saldivar had freaky stamina, and nearly always broke his opposition down due to it.
Fenech could set a truly phenomenal pace and maintain it consistently throughout a whole fight, even if it was a grueller. Always one of the first names I think of when this question is asked. Harada, too.
When did Hagler show this? Never. Antuofermo fought better the second half of thier fight. So did Duran. Leonard held him off. No Marciano like engine or unstopping style.
You're talking Frazier. Ketchel. Greb. Pedroza. Arguello. Basilio. Fullmer. Canzonari. Duran. Antuofermo. LaVigne. Jeffries.
Aaron Pryor and Jeff Fenech come to mind. A couple that no one has mentioned yet, Kassim Ouma and Visily Jirov.
Margarito!!!!!!!!!!!!!!!!! A beast! Little Miguel still checks the under of his bed before he goes to sleep at night. Then he says a prayer thankin the LORD for the ref that saved his ass in fight 2.
