Did the Dizzy come out for any reason? Easy to miss the oil pump drive when it goes back in. A non-destructive test for 0 oil pressure, Pull the distributor(dizzy for short) and drive the pump with a drill. Adapters are at most FLAPS. Have some one watch the pressure gauge in the cab. If the drill makes pressure, then the pump is working. You will be able to feel the pump load the drill, that means it is working as well. If no pressure and no load..pull the pan and get close and personal with the pump and bottom end. If the pump is working. Then find out why it is not turning when the engine is running. There are reasons for no oil pressure. Some are mostly bad..and some are simple. Test the pump first. Only turn the engine by hand until you find the problem.
