With the engine running, check the voltage at the coil + terminal to ground at the engine block or alternator housing. It should be around 9.5-10 volts with the proper combination of coil and resistor. With a fully charged battery and the engine running at a fast idle or above, the terminal voltage at the battery posts should be around 13.5-14 volts.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!