OK you made me do it! I crawled my fat behind under the truck to look. There isn't any kind of hole there below the starter. Something just seems odd here. Any way you can post a pic of what you've got? It just seems very strange. Every 216/235/261 I've ever seen has the timing port above the starter, and I've never seen a plug in one, though I suppose they might have had one at one time.
