1. Dwell setting. 2. The vacuum advance in the earlier years was usually a steel line with fittings at the carb or intake manifold. The year specific manual would be useful in determining if it should be disconnected for the timing setting.
3. the knob was for changing the timing based on the grade of fuel you were running. again the manual would explain this feature and the proper use of it. With todays gas you should not have to mess with it once you have the truck running good.
