do your homework on the oil pressure gauge,
some of the old gauges did not read in #psi
they only read as green/red or high low.
with these gauges you really did not know what your oil pressure was.
I had an old AC D14 and its normal oil pressure was around 12-15 psi,
so if you installed a 60 psi gauge on it, the oil pressure looked low all the time. I was able to find a 20 psi gauge and the needle stayed in the center of the gauge.
you want your gauges to read in the center of the dial at normal operation.