UFC's Max Holloway Down to Box Floyd Mayweather, 'I'm Not Scared!'

If Floyd Mayweather is serious about boxing a UFC fighter, Max Holloway says he's ALL THE WAY DOWN!!

The reigning UFC Featherweight champ has a solid stand up striking game -- and sources tell us that's exactly what Floyd is looking for in his UFC opponent.

So, when Max rolled through the TMZ Sports office ... we asked if that was something he would seriously consider.

"I want a Money Belt! Why not?!"

He added, "I would love to do that. He's one of the best guys to ever do it. And, to share the boxing ring with him, it would be a checklist for sure."

Holloway says he's already in INSANE shape -- and 12 rounds in a boxing ring would be "easy work" since he's already a cardio machine!

But, even if the Mayweather fight doesn't work out, Max says he's still interested in taking a boxing match ... especially with Dana White gunning to launch Zuffa Boxing in 2020.

Max says he's always wanted to box -- and brags that he's got a pretty solid Philly Shell ... but first, his focus is on beating Alexander Volkanovski on Dec. 14 at UFC 245.