Oo cold start-up, my olde Volvo MD17c will have an oil pressure of about 55 psi at approx 1800 rpm.
At steady-state operating temperature, and it takes some time to reach it, the oil pressure will be about 32 psi.
As the oil ages, that will drop very slowly.
Bodog is right, oil temperature has a huge effect on oil pressure.
Try both motors stone cold, and worked at the same rate thereafter. Al eyes on those guages.