This is a new engine right? It ran fine on the dyno? It isn't the rings and the stem seals, they didn't go away overnight on a new engine.
This is something that those 4 cylinders have in common.
Disconnect and plug the Pvc hose from the intake manifold and run the engine. See if it clears up.
Fords tend to syphon oil out of the valve covers into the intake manifold though the PVC hose.
If it isn't the intake manifold gasket, it sure could be the PVC.
Or what did you do to it since the dyno, change the cam?
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