Oil Gauge Issue

[rosseich]

I have a '95 ZR1 with about 10,000 miles which I recently purchased. The oil gauge is normally runs just below 80 PSI on the gauge at about 2500 RPMs, but at times the gauge drops and reads about 40 PSI (middle mark). If I turn the engine off for a couple of minutes then the gauge again reads almost 80 PSI (upper mark). Two questions. Is there a way to install a mechanical oil gauge on the LT5? Could the gauge be failing or is the oil regulator valve bad?
​​​​​​​Thanks.