Somehow oil is being pulled into the main plenum of the intake.
Mine started about 2 weeks AFTER I finished doing heads (completly rebuilt) and cam. Since then I have:

1. Replaced the PCV valve, even tested with PCV disconnected.
2. R & R the intake w/ new gaskets again, R & R the pipe plugs on the botttom of the intake as well.
3. R & R the head bolts between the intake runners with silicone under the head of the bolt and washer this time.
4. R & R the intake rocker studs.
5. Used ARP thread sealant on all bolts involved above, again.

It does take at least a couple of minutes from a cold start to begin smoking. I removed the throttle body to discover the thoroughly coated inside of the intake, its even on the backside of the t.b. blades.
My next guess is that for some reason the intake is not sealing. I did it by the book, no sealant around the ports, felpro gaskets. I have healthy arms and the manifold bolts are extreemly tight. I didn't use a torque wrech with the fuel rail in the way but I'm confident they're tighter than specs. If the bolt holes line-up then its positioned corectly AFAIK. The intake is just a guess as I am still unaware of where the oil gets in. Any ideas guys?

 

Its common for oil to come in the fresh air inlet for the PCV system.. the hose going from the passenger's side valve cover to the throttle body. Clean air is suppose to go from the throttle body into the valve cover but, sometimes go backwards when there is blowthru. Might pull the hose off the throttle body while it is running and see if you smoke coming out of the hose from the valve cover to see if you are having a lot of blowthru.

 

I check the other hose as well. Sorry, I should have clarified. No hose(s) to the crankcase are connected for testing. No significant blow-by either.