I have a 1968 GTO convertible. The VIN number indicates it is a real GTO. It has a 400 auto/with factory air. I have been trying to determine if I have matching numbers. the production number (last 6 digits) of the VIN are 115527. On the front upper passenger side of the engine block there is a six digit number (464430) with a YS below that. However, when I try to look down on the lower passenger side of the block near the timing cover (which is where I was told the engine serial number would be (that should match the last 6 digits of the vin #) I can't see a thing. I don't know if the water pump is just in my way or if it is totally covered up by something else. Has anyone else had this issue?