I just rebuilt my 454 (.30 over = 468), put in a lot of new high performance parts including a melling oil pump. Got the engine in the car, started it, set the timing and let it idle for about five minutes, during this time I noticed the oil pressure gauge needle start dropping from 70 psi to 20 psi. It seems as soon as the engine gets warm the pressure starts to drop. iT HAPPENS OVER AND OVER. I changed the oil pressure gauge to see if that were the problem, gauge works fine. Put in sae 50 weight oil, pressure still drops.
SOMEBODY PLEASE TELL ME THEY HAVE HAD THIS PROBLEM BEFORE AND KNOW HOW TO FIX IT!