This, in my opinion, is generally a bad idea if you are using conventional points or Mopar ECU.
The reason is the original design itself!!!!
These were all designed to OPERATE thus:
With the engine running, the battery/ system voltage is actually 14V, not 12. The coil, operating through the ballast, depending on RPM, sees something on the order of 10-12V when running.
BUT WHEN STARTING the battery voltage is NOT 14V, it's not even 12V, and in the cold of winter, hard starting, flooded, or if the battery is down some, actual cranking voltage at the battery might only be 10V
What this means is that if you STILL HAVE the ballast in the circuit, the actual voltage to the COIL under this condition will be VERY low.
So ALL manufacturers, Ford, GM, Chrysler, AMC ALL of them used the same design --- a coil / resistor combination, which IS BYPASSED during cranking to give you a hotter spark
Using a coil designed for 14V destroys this design concept.
Now, if you want to use a CDI type ignition, or HEI this is no longer true. In the case of my backyard HEI conversion, I'm only using a stock factory coil with the resistor bypassed, so in this case the HEI produces more spark and certainly "at least as much" as the original system.
