IF there is any exposed metal on those gally plugs still.. AND YOU ARE VERY COMFORTABLE with an oxy torch and have one.... pinpoint heat the plug and quench with WAX....
I wish I woulda been here before you did the head, I woulda told you with the head OFF to apply pressure to the outlet hole of the oil filter housing and make sure it came out the oil gally that heads to the head. IF you want to consider it, its risky, but you could pull the front passnger side headbolt and test the same, BUT when DONE you have to make a small tube to suck ALL OIL out of the bolt hole...but it would tell you if the oil is making it through the galley that goes to the head
