Two bolts hold your
oil pump to your block but you may also need to remove your pickup (another two 9/16" bolts). What kind of distributor do you have in your engine? Your distributor drive shaft sets in the top of your
oil pump and has a washer at the end of it that prevents you from pulling the
oil pump shaft out when you remove your distributor. I would certainly pull the oil pump and remove the inspection cover to make sure there is no debris lodged between the rotating gears in the pump. You will probably need to replace your oil pump M-57 normal or MHV 57 high volume part numbers. I personally run the High volume pump w/ the larger oil pump drive shaft. But given all the varied opinions here I would say replace it with what your engine builder recommends.
Clois