The voltmeter is reading an average of the "points open" voltage (charging system voltage) and the "points closed" voltage which should be close to zero. Tha 8 volt reading sounds about right if the point gap is set properly.

The coil boosts the voltage at the center tower, the one that goes to the middle of the distributor cap. There's absolutely nothing wrong with your ignition system- - - -if the engine runs, don't over-think it! Drop me an email if you want to discuss the operation of the coil without getting a lot of conflicting opinions- - - -I've been teaching ignition system theory successfully for over 30 years to a bunch of high school students the counselors think are too dumb to be in regular education classes like "music appreciation"!
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!