Hey guy's, trying to check timing on a Duster I recently bought. it's a '72 with supposably a S/6 transplanted from a '78 Aspen but not sure if it is a '78. anyhow my question is: the numbers on the timing cover are rusted and unreadable.is TDC the tube or one of the unreadable numbers that are counter clockwise from the tube? I think I can make out the 10 deg. mark, but there is one inbetween it and the tube and I don't know if it is a 5 deg. or that is TDC. Thanks