my big block used full groove main bearings (full time oiling vs half with stock bearings) and an High Volume oil pump, and it had the following numbers:

with 15w40 oil:

PSI at cold engine start up 75 psi

hot idle 30 psi

hot cruise 45-50 psi below 2000 rpm, and 60-65 above 2000 rpm.


switched to 10w30:
cold start up 75 psi

hot idle 20-25
hot cruise below 2000 rpm was 40 or so, and 55-ish above 2000 rpm.


knowing if you have full groove main bearings or not would help, as well as whether or not it's a stock pump or HV pump. (you said "high performance OEM type)