Noticed the cap terminals have the arc marks off to one side so I did the old hole in the cap and watch the rotor with the timing light thing. At idle the spark looks to be jumping when the leading edge of the rotor blade is even with the leading edge of the terminal on the cap or even a little before. Disconnect the brown wire ( 0 degrees ) and the spark happens when the trailing edge of the rotor blade is about 3/4 of the way across the cap terminal. Question is what is the max advance on the TBI set up and when is it programmed to occur? Didn't the old mechanical distributors advance the rotor with the centrifugal advance to keep the rotor blade pointing at the cap terminal? I have the feeling I'm missing something here, but what?