TOO MUCH OIL PRESSURE

I have my doubts that you will get it to hold 100 psi regardless of which gasket you use.
Why do you want that high of pressure?
10 psi of hot oil pressuse per 1000 rpm.
7000 rpm = 7X10 or 70 psi on the big end.
I agree I installed stock pump from high volume pump trying to lower oil pressure same oil psi. How can you can psi out of oil pump?