Today I started up my 454 getting ready to break in the cam when I noticed that the oil pressure slowly dropped from 20 to 0 after it warmed up and never came back up. I am using Rotella Diesel 14w30 and pan is full. I stopped the engine and first check my oil pressure gauge line that is tapped into the oil filter housing, no kinks everything looks good, then I removed the gauge and tested it. Gauge tested OK. Then I decided to remove the distributor and everything was intact. Next thing I did was remove a valve cover and see if the pushrods were getting any oil. Once I fired up the car there was no oil coming out of the pushrods, I promptly shut the motor off and I am now stumped. The oil pump is brand new and installed correct as it was working previously and randomly quit. Only thing I can think of is that the oil pickup may have fallen off but that just seems unlikely due to the fact I tack welded it on. Any suggestions? Thank you in advance.