Z would win with difficulty. He would have to dodge and trow the bijuu bomb aside with his arm, and make direct frontal attacks. Naruto could try keeping his distance, but Z can keep up. He wouldnt explode a Bijuu bomb on himself so he'd try to do h2h which Z is much more superior in. His arm can stop anything such as the Rasenshuriken or a rasengan with ease
Hmm the only thing I can see with a problem here is him getting away from a bijuu bomb explosion. He is definitely leagues faster than naruto in reaction speed and way superior in h2h combat and could even 1hit naruto if he gets in close range but my only argument here is what happens when the bijuu dama comes into play. I don't really remember seeing him move that fast in terms of covering distance to avoid the blast but I guess if he hit it with his arm and with haki behind it he could try to knock it away. That is my only query.
If Z does what he has shown to do he will close the distance and 1hit naruto and if that doesn't work he will just cold hearted all gloves off gangster shoot naruto. Because apparently he uses guns.