TBH I think this has more than one issue and I agree the dwell does not look right. Two long, two short - hows that fit with cylinder comps? Amp clamp?
Agreed, iirc compression's been checked ?
In theory, Yes.
But your second question disproves the first. For example if I grounded a plug lead would you expect to measure no induced voltage in the primary.
Not sure I understand the underlined part ? but interesting, so i had to go experiment ...........
The plug lead was grounded (direct short) via a fly lead to the battery clamp, no change in the primary EMF kick but no secondary kick at all, but the spark line still mirrors..... would be interesting to see the effect through a high resistance resistor ??
Same primary/secondary not grounded.