What would cause the oil pressure to become high? on a 85 12a with 60K miles with all original factory equipment, e.g. no modifications - using 10/30 oil as always

Until recently, it has been reading slightly to the right of 60 at speed, now the guage is reading somewhere around 100 and drops back to slightly to the right of 60 at idle

Is it safe to run it with this much oil pressure?

 

i think that maybe your sender is shot. mine does the same thing. beat it with a hammer and see if it goes back to normal...