Are you using an oil pressure gauge on the oil galley by the points to show actual pressure vs just the dummy light?
Drain the oil from the pan (if there is oil in it!), drop the oil pan and remove the pump. Soak it in oil covering the screen, turn the gear to burp out air and reinstall making sure you have the O-rings in place. Pour 2 quarts down the drain holes in the head behind the caps in the valve cover to get plenty of oil into the pan.