For some reason, when GM went to 12v, a resistor (called a ballast resistor) that reduced the voltage to about 9v (I think) was required in-line on the power lead into the coil. Some coils came with the resistor built in. Some (maybe all) of the Petronix Flamethrower coils have high resistance and no ballast resistor is needed.
If regular 12v points were used without the resistance, the points would burn out in a very short time.
http://www.google.com/search?q=ball...ved=0CDUQ_AUoAQ&biw=1024&bih=644
