Electrical problems

Measure voltage from coil+ to ground with key in "run." You should have less than 12 (assume you still use a ballast?) and that should be about 6--10

Now crank the engine with the key and watch the meter. Should be very close to the same as battery. Measure battery + post also cranking to get that reference.

Don't know why the charger would have burned up the Mallory, did you leave the key on?