383 lost oil pressure

If this isn't your oil pressure issue, it's possible you sheared the oil pump drive.
Pull the distributor, after marking it's location, and the rotor location. Note the position of the slot in the top of the oil pump drive gear. You will want to put it back the same, to keep everything where it was.
Get a pair of long needle nose pliers, and grab the gear you see down there, and pull up with a twisting motion to remove the oil pump drive shaft/gear. See if the bottom tip is sheared off. But repair the valve train issues first. Then see if you have oil pressure. The lifter being part way up, could be uncovering the oil hole to the lifter, killing the oil pressure.