Bulent,

  There is a control valve next to the oil pump and a pressure regulator
on the Rear housing (I think that is how they are referred to).  The control
valve is a sort of safety feature set for approx 156 psi so should you plug
your oil line you don't blow the line.  The Pressure control valve generally
dumps oil to relieve pressure around 70-90 psi (depending on which one you
have and/or whether you have shimmed it for increased pressure).

The only thing I can think of is if you wanted more oil pressure, folks have
shimmed the pressure regulator with some spacers - but, I would probably not
do that as it works the pump harder.

Ed