The only time the resistor will show a voltage drop is with the points closed and the ignition on. If the points are open, you'll see 12V on both ends of the resistor. With the engine running you'll see battery voltage at the upstream end of the ballast resistor and 9-10 volts at the coil + terminal, if everything is wired correctly.
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!