Bill, I don't see a PCV valve in your pictures so I guess you have none at this point? You said, " I removed the stock PVC valve from the intake manifold" but you didn't say what you did with the valve and/or plugging the hole in the intake manifold (from the removed valve). So judging by your pictures, a small amount of vacuum is created by the carburetor inlet air moving past the connector that you welded into the air cleaner.
Attached pictures are of a 1948 GMC with the system connected. Ignore the rubber hose that was disconnected from the gas filter. I think the original flow is as follows: The oil fill is part of the draft tube which is vented (I think). So flow is from the draft tube, crankcase, lifter galley, head, valve cover, tubing, PCV valve to intake manifold vacuum.
I think having an oil trap inline with the PCV valve, regardless of where it is connected has merit. Oil and sludge can cause the valve to stick. Being the internal spring is trying to push the valve wide open (engine not running), this is where the valve sticks after the engine cools down. Wide open valve means lean fuel mixture.
To me the Chevrolet location of the PCV valve above the closed-up draft tube would be better to avoid oil related problems.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
