New head, low oil psi, 50% jake

[Mr Hagg]

Id pull valve cover and run truck. Id be looking for excessive oil leaking. A few things Ive seen in the past are:
Rocker shaft not properly seated to head causing a lot of oil leaking.
Jake solenoid plate that bolts down on top of rocker not seated( this will leak bad to)
Or the solenoid it self could be just dumping oil from bottom.

Also look at cam bearings to see if any of those are leaking good. Being jakes are weak to Im leaning towards the fact that its something in the head and or rocker area that is the issue.