I was looking through a box of small parts a guy gave me and came across a strange tool that I'd like to find instructions for. The gizmo is called "DIAL-A-GAP". It has a hex bit that fits into the points on any 1957 to 1974 (pre HEI) GM distributor with externally adjustable points. I found an online picture of one, but no instructions. You can see a numbered scale in the picture 0 thru 9 and there is another 0 thru 9 scale on black with white letters on the other side of the dial. The flat of the knob has an arrow pointing clockwise with the number 1 and an arrow pointing counter clockwise with the number 2. Anyone know how to use this? Know where I can get a copy of the instructions?