|Naruto and Luffy from One Piece|
Luffy might be resistant to physical hits, yes. But Naruto probably wouldn't try that for long before realizing it wouldn't work. Rasenshuriken would totally eviscerate Luffy's muscular and vascular systems and render him totally defeated. And Naruto can summon multiple of these, the size of houses. Speaking of summoning... it might be hard to defeat Gamabunta for all Luffy's strength. Not impossible though, he would probably succeed in putting Gamabunta down.
Naruto's speed would be an immense problem for Luffy. I know he has certain reflexes and almost premonitive anticipatory abilities, but that says nothing about his actual ability to evade. Naruto's movements are faster than even the most powerful eyes (The Sharingan is said to be able to track with perfect clarity and precision) can see and he can appear from any direction and strike before you could possibly know he moved. He can use shadow clones and overwhelm you (at these high speeds no less).
I have no doubt that Luffy could severely batter and maim Naruto with his strongest abilities. The problem is Naruto is far, far, far too fast to be hit and even when he does get hit, he can really take it. His healing factor also helps. His basic technique Rasengan is a game ender, and has even been shown to brutally maim characters who exhibit elastic and rubbery bodies normally resistant to bludgeoning and slashes.
Sage Mode is another hairy technique to face. That would put him on equal odds with Luffy's physical strength and speed for sure, with the added bonus of being able to sense him at a distance without sight.
It really is a one-sided fight. Luffy is impressive with his strength, but he isn't really fighting characters of astronomical size or power, which is what Naruto is equipped to face. (They literally have to fend off an island size meteor, which is a regular technique by the final villain.)
That being said, I'm pretty sure the Frog Song would be checkmate, if Luffy allowed it to execute, which is likely, because he would have no way of catching Naruto if he tried. Luffy has no defense against genjutsu.