I have a 1992 gen I block and the oil galley holes are .570 on the sides and .500 in the middle hole. Is this common on the newer blocks? This was a GM rebuilt engine for a 87 el camino I picked up for my vega project. Less than 5000 miles and the crank was scorred so I pulled it down and had the block cleaned. Every engine I build I always Tap and Plug the galley in front but this one has thrown me for a loop. The local Chevy dealer told me he doesn't have the plugs and I would have to order them and buy a box lot. Any suggestions on this. Should I order the plugs and stake them ? Will a 3/8 plug be too thick and block the oil passage? HELP !