ya, im talking lugging.
WoW! 60-40psi!??!!!
Mine does maybe 40psi cold 10-20 hot!!!!
Hell, my old 4.0 would get into single digits on idling on really hot days.
Yikes! 10-20 psi! How many miles? You may want to double check the reading is accurate and then step up to the next weight of oil if it is in my opinion. That's my 2 cents, for what it's worth.
My '83 RV started running 10-20 psi hot, even with 15-50w. Put an analog gauge on the oil pressure port to confirm the low PSI when hot. I took out the motor and found worn out crank bearings, it was a grenade waiting to go off. Ended up happening because of an oil bypass ball valve snapped, bypassing the oil filter, starving the main crank bearings while I was towing my jeep. Only got about 3 camping trips before the motor had to be rebuilt.