Cam/Head Swap Disaster.......

Imo, the trail coming down the valley from the head gasket tells the tale.
Just put some stock replacement Fel-Pros on it(8553)........ don’t worry about the 1/2 point of compresssion.

The high oil pressure has nothing to do with that coolant leak.
It’s a separate issue.

Pull the oil pump apart and see if the relief valve is stuck.