Treblig,
The protractor was used to determine the true mechanical advance in the distributor. What I did was bent over a cotter pin and tape it to the rotor, then positioned it at 0* with the shaft of the distributor locked down with the vise grip. I then can then turn the rotor and figure out the mechanical advance. In this case it showed 12* on the protractor. You then have to multi by 2 to get crankshaft* so therefore my distributor had 24* mechanical/centrifugal advance. I wanted to be around 18* mechanical so I loosened both adjustment screws in order to take out some timing. I set it at 8* on the protractor multi again by 2 and I get 16* of timing in the distributor. Now I can run more initial timing which ill set at 18* to give me 34* of total timing. I hope I answered your question. Thanks again Treblig...oh by the way your exhaust manifolds are still working great on my car.
