Finally! Oil pressure is back! It has been quite a journey. I installed the new Mellings oil pump, filled it and Fram filter with STP, and tried to prime the engine with no success. The red dash oil light stayed on, and the aftermarket mechanical gauge under the dash showed no pressure. This was not the result I had hoped for.
Next, I drained the oil and pulled the oil pan. The oil pick-up tube was tight in the block, but I removed it for a closer inspection. Upon looking the tube over closey, it looked to be bent/kinked at the screen end. I sourced a good used tube from a friend and installed it. I put a blob of PlayDoh on the bottom of the sump, and pushed the oil pan up into place, to check position of pick-up screen. This showed a measurement of 7/16" , which I figured was fine. The pan went back on, and a new Fram filter went on. I wondered if I might have plugged the previous filter with heavy STP.
With my wife turning the key to spin the engine on the starter, and watching both the red light and the aftermarket oil pressure gauge, I spun the pump CCW with my drill motor. My wife reported that the red light never went out, and no pressure showed on the gauge. This was not good. At this point, I just walked away from the car for about a week.
About 10 says ago, a couple of friends stopped in to see how I was making out with my Polara. Both of the guys are Hemi NSS racers that build their own engines and are very knowledgable on big blocks. I told them what I had being going through trying to get some oil pressure. By this time, I had removed the fitting and plastic tube that fed the under dash oil pressure gauge, due to a leak I had found there, and replaced the gallery plug. These guys pulled one rocker stand off. One guy ran the drill motor while I turned the engine over with the starter. The other friend verified that there was oil at the rockers. Next, the plug was removed from the port that had supplied the aftermarket oil gauge, and we repeated our test. My friend verified that oil squirted out here. They suggested that I plumb a mechanical gauge to this port to verify what oil pressure I actually had. They also suggested that I get a new switch for the red dash light. With all this spinning of the pump, the red light had continued to stay on. One of the friends also suggested using a Wix filter instead of a Fram, since he had seen too many Fram filter failures at the track in his years of racing. Pulling both the valve covers verified that there was nothing wrong with the valve train. All the lifters and push rods were right where they were supposed to be.
