The math part is finding 5 degrees btdc on the flywheel. So 360 degrees divided by 139 teeth (6 volt flywheel) = 2.6 degrees per flywheel tooth


1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration