Oil pressure-How much is too much?

Why not just try taking out the Oil Pump Pressure Relief Valve(Big Nut on the side of the Pump), accessed externally on the outside of the pump, see if there is anything you can do to lower the relief spring pressure itself... let it dump back at lower pressure ?

Sometimes they have a small washer behind the spring ? Remove it, as long as the Nut Housing Bore still has a seat for the Spring, or add washers on the large external Nut Housing that you remove to access the Spring ?

If still gunga pressure, even with thin Oil....clearances are too tight.