Hey Stihl011,
As krazykuda said, a separate gauge,preferably a mechanical one temporarily screwed into the sending unit hole in the block,is a much better way to check oil pressure. I was going to mount one inside my cuda permanently but members on here convinced me not to as if the oil line broke, it would dump oil into the interior of the car. Point taken.
Here's something you can check that I ran into with my cluster resto. Make sure the gauge housing behind the clear plastic lens is not hitting the gauge pointer. (the circular black piece with the chrome trim ring). I was chasing this problem forever until in desperation, I took the cluster back out and discovered the orange pointer was hitting the plastic housing about 1/4 way up the scale. Probably happened when I was pressing in on the cluster to re-install it. If your oil pressure was ok before you took it out, its a good bet there is a problem with the gauges and not your engine.
