BAsque 1 If the smoking is only on shifts and not startups also, it could be mechanical. This also depends on which valve stem seals are in the heads.
Some guys still use the old umbrella style and they weep down the valve stem and into the cylinder. They are cheap and easy to buy. When vacuum is applied to them, the
oil is sucked through faster and you get a smoke trail alot of the time. Pos seal ones have a circle clip on the top of the seal to stop
oil from going down the stem, even under vacuum. Alot better seal.
Leak down test and compression test are not much help in this case.
As far as an
oil oriface in the heads,DEPENDING on the rockers, .085" is for street motors. .065" is for race motors on the track. I tryed .065" with an hvhp oil pump and found that a blueing was happening on the adjusters and tips of the pushrods. The other thing is the spring produce alot of heat. They need to be cooled off also. My heads are flooded to the holes of the intake manifold. I also have a 12 quart system. I have Erson rocker setup and don't run tins for return flow of the oil in the heads. This was on cast FE heads and my Shebly ones now. Run your motor 1-1.5 quarts over full any way. Over 30 years I have never seen a motor destroyed from too much oil, just not enough oil to the correct places. Have to also remember this is an FE Ford motor not a SBC one. The reading you see at the guage IS NOT what the pressure reading is at #4 and #8 rods or the heads, unless the motor is a sideoiler. JMO Rick L.