I got a 71 duster w/ a 360 and having timing problems. I set the base at 10 degrees and checked the total timing at 300rpm and it is 45 degrees. Set the base at 0 and still went to 45. At 2000rpm the total is 35 degrees. Tried adjusting the advance and no change. Screwed ( turned clockwise) the advance in till it stopped and no change. Any advice?