Stock oil gauge are very inaccurate and very slow responding.
After years of disatifaction and worry I undertook a very overengineered and heavy duty aftermarket( Autometer)mechanical oil gauge installation. With suggestions from folks on here to improve responce and accuracy , I now have no doubt were the pressure is at all times on my 3.0 SOHC.
20/50w castrol
ice cold idle: 80 - 100 psi.
hot idle : 15 to 20 psi.
under load on flat highway at 3000 rph in 5th: 50-60 psi.

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.