FBO's black HEI ignition box

Post #19. Higher amperage. One of the limitations of points ign & the Chrys ECU is the current a limited by the coil's primary resistance & the bal res connected in series with it.
The power [ energy ] in the spark is P= volts times amps, in simple terms. More power creates more heat & it is the heat that ignites the mixture [ not the voltage, it merely enables current flow ]. Lower resistance, more current. The high resistance of the Mopar coil [ about 1.5 ohms ] + the bal res limits current. The MSD 8207 coil has pri res of 0.35 ohms..& no bal res to further reduce current. Original OEM HEI coils had about 0.5-6 ohm.
So by increasing the primary current [ 7.5 amp ] , you increase the power of the spark. CD igns produce very high spark power, but about 1/10th the duration of inductive ign such as Chr & HEI.
GM specified 0.060 " plug gaps [ 0.080" for some engines ] & common sense tells you only a powerful ign system could fire a gap that large.