Good question. Both were underrated punchers and have stinging power that hurt although Mayweather was probably a harder one punch hitter in the lower weights. I also think Mayweather might have more power than Whitaker as he moved up in weight. So FMJ gets my vote.
Floyd's lead left hook was fast and powerful, he dropped many guys with that punch. I remember whitaker dropping uncle Roger with a left as well and didn't he spark out Hurtado cold? Whitaker had deceptive power for his size.
You must be saying 5`6 is short for a welter because a lot of lightweights were 5`6, why did you mention a short American wrestler?
It's clearly Floyd, although neither of them were big punchers obviously. Floyd's power is frequently underrated due to a combination of him slowing down and not bothering to go for KOs as he got older; along with the amazing level of toxicity from the casual fandom who believe he was a feather-fisted runner/hugger (which I never understood since Floyd honestly didn't do a whole lot of lateral movement Ali style dancing and he didn't excessively clinch either). Floyd could wear guys down with his accumulation of sharp, stinging, accurate combinations. His single punch power was decent too as his jab alone could sometimes stop a guy dead in his tracks when he sat down on his shots. His left hook and right hand lead were both solid tools with decent power even as he got older and had hand issues: no one just walked through his punches like they were nothing.
Whitaker had way stronger opposition in his first 16 fights. Floyd's opposition during that fights was honestly weak so he scored 13 KOs. Whitaker scored just 9 KOs but his opponents were generally better. After moving above featherweight Floyd scored just 7 stoppage wins in 23 fights (including cheap shot KO vs Ortiz and stoppage against pro debutant McGregor). Whitaker's results are close as he scored just 4 KOs in 13 wins above lightweight. None of them were punchers actually, probably 5 on scale from 1 to 10 to speak generally. Floyd had like 6.5 power at 130, but more like 4 on a 10 scale at 147 and 154
Whitaker's brutal KTFO of Hurtado and demolition of Nazario easily outshine any display of Floyd's power in his 50 pro fights
Mayweather I would say - incredibly good power… his style and hands influenced his style a lot much like Muhammad Ali who could punch but his style and hands took priority.
Mayweather could really hit man I’m not a fan or anything like that but he was no joke when he wasn’t worried about his hands and got set… Hatton had an anvil chin and Mayweather cracked it for good.
I disagree. This is a myth that Floyd couldn't punch because he had injured hands. He was not featherfisted surely, but not a puncher too. Look at his stoppages at 130, he landed numerous combinations of punches before opponents were hurt/quit (Corrales was different but Corrales was dropped and hurt in numerous other fights). Floyd was never Roy Jones in terms of power in any division. Hatton's chin wasn't elite - Pac KO'd him cold for a few minutes, and very early in the fight. And Pac was far smaller than Floyd - that's a fact.