Easy thing to do is post pictures of your setup so we can see the waste gate to tell you if it's hooked up right.

Boost can change on the street because of different loads an cooler air.

 

ill try to get some pics. anything specific?

 

Pics of waste gate an hose routes for start

 

Both O2 in down pipe is not good.
Move the driver side front O2 back to the proper side.

 

Tuner still has the truck right now. He swaped out wastegate spring and was able to make more boost. He is doing some other things i asked before taking it back to the dyno. (Making fans and fuel pump no longer on switchs). Currently the o2 sensors are turned off and hes gonna use the wideband signal wires to tune again.
Im still confused why the truck is not closer to 500hp like everybody elses setup though. They say its the turbo and stock motor...

 

It sounds like you have misfiring problems (might not be noticeable), a stock cam, a small turbo, and have had your expectations inflated by the internet. Actually making good power is not as easy as the facebook warriors would have you believe just by throwing on a turbo and cranking it to 15psi. It takes time, sweat, energy, and money to make a setup that is both reliable and makes good power and performs well.

 

is there a way to detect a misfire if you cant hear or feel it?

I thought a 78mm turbo was actually a decent size not actually small

I understand the whole money sweat tears etc, this has nothing to do with facebook, i look through other setups and usually see more then what my setup is producing. Now you could be right, where they have more mods then they say, if so then im wrong. if 380 on 8psi is normal then its normal, ill be sure to post for the next guy to see. but if it seems low and likely a problem then id like to fix and be true

No updates from the tuner yet

 

What did the truck Pre-turbo?
Did you move the o2 to the driver side?

 

install driverside narrow band in its stock location
install pass side narrow band in the log where KB places abung
install wideband in the downpipe

tell tuner to turn narrowbands back on

 

Probably a silly question, but what is your axle ratio and tire size?