I will be going over tonight to run compression test, and maybe leak-down too?
The spark plugs (from the photos) did not look too bad? The body ring of the sparkplug that goes in the chamber looked sooty black from idling, but not oily?
I am also thinking the smoking only starts after the engine has got to temperature. Oil still looks near new, constant 50 psi oil pressure (stock oil pump.)
could it be some coolant getting past the head gasket?
The cooling system does seem suspect, as it seems we are not getting any pressure when the engine is hot?
Running cometic head gaskets, and the block deck finish looked pretty smooth. The TF240 heads were checked by my cylinder head guy, and said they were good, but not sure if he checked the valve guide clearance?
The engine went together with no issues. Checked all the bearing clearances, side clearance, thrust clearance, rings gapped at 0.020". The engine spins over really nice and smooth.
I did use a Comp Cams Nylon thrust button for the first time, but there was about 0.010" clearance to the cover.

Maybe I will pressurize the cooling system and check for pressure loss?