It depends on how much fuel you put through them. You can get just 50hp out of them, or 200. The turbo housing won't add power, just change the spool characteristics of the turbo.
Once you get big injectors like POD's, your biggest obstacle for a long time will be getting the air in to cool off your EGT's once you get all that fuel in. That happens whenever you add fuel.
You'll need porting work, a bigger turbo, intake, exhaust etc. to get more air.
Make sure and add a signature via your user control panel so we know what is already on your truck.