Hey buddy,
Tell us a little more about the car and what you have.
On my 260, I had the oil gauge issue. What I found was the connector to the sensor was pretty dirty and loose. I needed a change of underwear when on my freshly rebuilt engine I lost all oil pressure while pressing on. 'Twas just a loose connector.
Oil pressure varies greatly on these engines. I find idling for a while I get a quarter on the gauge and pressing on it sits well over three quarters. What is important is that the oil level is at max and removing the oil filler cap you see the cam spraying oils around. If you have those conditions then highly likely you have an electrical issue.
Check / clean / tighten electrical connectors first. If you ground the fuel sender one under the car, you should see the gauge go max. Same with water temp and oil sender wires.
As for the clock - most of them stopped long ago and need a recondition!