Hey Chris: Since you had the block stitched and there is a slight air leak in it (which is common), you should think about starting it up and using some water-glass type sealer when you first break it in. I had the same situation on a recent build and due to the slight air leak, I didn't want to risk a water leak, so I bought two cans of the following and followed the directions EXACTLY as they say:
https://www.jegs.com/i/Moroso/710/35500/10002/-1
Better to be safe than sorry on a repair like this! Best of luck on your show.