I have a 41 - 216 engine that runs, but when the pointer on the bell housing is aligned with the "BB" on the flywheel the engine backfires when reved-up. It also will not start when turned off.
When I adjust the timing by ear and no back fire, the timing mark is way out of sight, past a triangle on the flywheel.
Is the timing adjusted with or without the vacuum advance connected?
If the distributor was put back in one notch off when it was rebuilt, would this give rise to all of the above??
Is the point gap of 0.018 correct? What would the dwell be? (is this the same as cam angle of 38 in the old "motors manual")

41 Chev 2dr coupe
51 3100 w/a 261
11 Camaro RS ragtop