Putting in a 307 motor and working on the starter now. I see the three holes that the starter can use in which I have the 168 tooth flexplate so using the staggered holes from what I have read. But along side of where the inline bolt holes are there is another hole that is larger and I cannot figure out what it is. It is very close to the oil pan. Anyone know what this hole is for? I'm trying to get a pic but thought I would ask first. Thanks.