Confusing oil pressure 3.6
 

I have a 1990 3.6 in a 1980SC with dual Carrera coolers (in series with 7/8"hose.). Oil pressure when hot is about 1 bar at idle and only goes to about 2.5/3 bar at speed (@ 2500 rpm+) Cold press is about 2 at idle and 3.5 at speed. Indicated temp remains normal .Guage and sender were from 3.0 which showed same idle but 5to6 at speed. What could be causing the LOW high rpm pressure? Worn bearings or pump would typically lower pressure at idle as the slower running pump can,t keep up with demand.Oil in it now is a blend of 5w30 synthetic and 20w50 dino.I am going to change the relief springs and or shim the relief if no other answer comes to mind