Well I tried switching to a lower visocity
oil (5W-30) and that did not help. So I decided to tear of the
oil pan and check the
oil pump.
After comparing the installed pump with a brand new standard volume pump it turns out I had a high volume pump, not a standard volume as I assumed. The depth of the pump rotors were deeper than the standard volume pump (more surface area, hence more volume.)
Anyway... installed a standard volume pump and now my oil pressure is 60-65lbs off idle with cold oil at start-up. By the time the engine warms up and idles steady the pressure is 45lbs. After warm and revving to 5000rpm the pressure goes to 65lbs max.
Sounds good to me.
Greg