I did a fancy screw in plug once with an o-ring seal and a bleed hole but it was a bunch of work. These days I just ream the gallery to the right size and press a plug in there with a 0.062 hole. That hole size is big enough to provide lots of lube for the lifters but it does act as a restriction if a lifter fails. It will also keep the oil pressure high with cold oil but the oil pressure bleeds down fairly quickly with hot oil.