I have an aftermarket 30 amp circuit breaker on my main electrical feed from the battery. If I forgot and left the ignition on (before starting) and the distributor/points were in a bad position, would the coil likely overheat/fail before the breaker tripped (assuming my grasp of electrical basics is accurate)? The breaker automatically resets when it cools, so any coil overheating would be repetitive.

6 VOLTS/POS. GRD. NW INDIANA

I don't think a coil could ever trip a 30 amp circuit breaker. Also, I was under the impression that if the ignition was left on with the points closed the result was burned points rather than the coil failing. Just my opinion and experience. 

As Gene indicated the points would usually be the first to fail. Coils generally draw about 3.5amps so it will never trip the breaker unless there was a short to ground.