I've been reading topics on this for the last week. I keep uncovering one more little bit of evidence at a time, but I'm really not sure what to pin this problem on. 
  
Setup: 
-Freshly rebuilt L28ET (approx 500 miles) 
-Stock turbo 
-Intercooler 
-Oil cooler 
-Ignition and fuel running on SMS (side note: if anyone has maps I can look at for similar setups, I'd love to see them!) 
-PCV on the valve cover is open to atmosphere, crank vent is connected to stock vacuum port on intake manifold 
-3AN oil pressure line to turbo (thus I've ruled out a restrictor issue). Stock drain tube from turbo to pan. 
-Stock injectors 
  
Problem: 
I'm getting lots of gray smoke out of the exhaust. Smoke is minimal to non-existant while everything is cool. After it warms up, the smoke is constant. It does not change with acceleration or deceleration. 
  
-No oil in the coolant 
-No oil in the intercooler pipes 
-Turbo appears to have minimal play, though I understand that is a subjective test. 
-There IS oil on the plugs. 
-All of the gaskets, rings, etc are brand new due to the rebuild. 
-There is no blue tint to the smoke, it's just gray 
-I tried applying vacuum to the valve cover pcv, but nothing changed... 
  
  
Ideas? Thanks guys!!!