Okay, I got home and pulled out my gauges. Here are the readings:

Idle
High Side: 250 PSI steady
Low Side: 55 PSI (occasionally varying between 50 and 60 PSI)


2000 RPM
High Side: 225 PSI steady
Low Side: 27 PSI steady

These pressures look about right to me, with my only real concern being the varying pressure on the low side at idle.

Do these pressures fall within the correct ranges?

__________________
1984 300SD
351,000 miles