Expected gains from a 5.3 2014 Silverado Z71

[MADWHIP]

Hi All,
So I had a 5.3 2014 Silverado Z71 to tune today. It's the first 5.3 I have tuned. No trucks like this were ever sold here in New Zealand. It made 278rwhp with a k&n intake and stock tune. I obviously had no starting point tune file so I just started from scratch. All I seem to be able to make is about 10 extra hp. Is this normal or is my tune junk? I have attached a copy of my tune file (v10) it still needs trans work and the fuel trims done I have also loaded the standard file from the truck. I would hate to think I'm sort changing the client on power but cant seem to make anymore power. If anyone out there has experience with these later 5.3's can have a look and see if I have missed something. These files are nothing like our Holdens. I'm not asking for a tuned file I just want a heads up so I can improve my game.
Cheers

[Rigo_eff1fitty]

what fuel are you using? also raise fuel cut off to 6600. these trucks like to shift at 6200

[IARLLC]

This has to be a direct injected GEN5. If you repost to the GEN5 thread you will get more responses.

I don't know how much to expect at peak rpm but I know it is possible to get solid torque gains down low on these GEN5 5.3 and 6.2.

[MADWHIP]

The fuel 91 in the us scale