My oil pressures never, ever, go below 60 due to my insanely critical bearing clearances and I run rotella 15-40. however, I use a 3" by 18" cooler and hold around 250 wot now. I would not just add a quart of oil until you have had a chance to do the wot test while watching the pressure gauge and hopefully while watching the temp. Unless of course you add the big filter as suggested by Patriyacht. You can drill and tap the top of the stock filter body for a sender or if you have the older ones there was an unused port you could use. SSComp has very nice inexpensive gauges ive used for years now.