I just rebuilt my 388 again and upon firing it up there is a light knock, but definitely heavier than a tap. One thing i noticed is that my distributor seats but when it seats I can move the distributor forward and back. It seats all the way down against the manifold, but i can wiggle it. 50 lbs of oil pressure at idle, no smoke comin from the tail pipes, no bad vibrations or misses, but a knock. took the pan off, nothing obvious. I fired the engine up and took one plug wire off at a time and the knock continued. pushed in the clutch to make sure it wasn't the transmission and it still knocked. Oil level full. Any advice would be much appreciated. thanks, Grant...