I think you'll find those dots are on those gears like Bob C pic. But Kurt is right, you can time the those gears if there is no marks on them. If the head is off it's easier but if it's on watch the 2 valve on no. one piston with the side cover off. Turn the cam and watch the exh. valve open and close, just before it closes the intake valve will start to open. if you rock the cam back and forth those to valves will rock back and forth, do that so both valves are off the seat, that's called valve overlap. NOW, somehow your going to have to see the piston and make sure it's TDC. mesh those gears together and the valve timing will be right. NOW, the problem is with the Model A-B engine, timing the gears this way the detent may not be in the right place for the timing pin in the front cover. SO, that's a little lesson on valve timing any engine but I think you ought to fine the marks on your gears. If the oil slinger is in front of the crank gear it's probably covering the punch mark on the tooth. Walt