Low oil pressure 15 lbs when idling 318

Hello everyone.
My 74 Dart 318 runs well with Edelbrock heads, intake, Purple stripe cam.
The oil pressure drops to 15lbs after warm up idle, and up from 40 to 60psi under throttle.
Should I replace the oil pump, and, can the pan be dropped without pulling the motor?

I now reside in Alexandria,Virginia.
thanks all..
O:)Dave Dume