Not getting 12 volts to coil

Yes, the wire with 9 volts under the dash and 10.4 in the engine bay was #16. # 18 (black) was confusing, as it seemed to go to 0 under cranking. All my fuses look old but unblown, except the extentions for the red and black wire coming into the box are exposed on top- with nothing over each one's stud sticking out. Yes, I did the voltage drop test from the alternator 'batt' post, and I assume I'm measuring the positive part of the under dash splice circuit, because if I were drop testing the negative part of a circuit , would I have the negative volt meter terminal on the alternator's body's metal body and the positive meter terminal on the battery's negative terminal? You've given me a lot of principles and clues. My car is supposed to be stock, but we were supposed to be virgins on our wedding night. The alternator is original, but a shop said it was good. I'm surprised we have not talked about the two connections on the ammeter gauge, but I'm glad, even if you may be testing me to develop a test that would infer something about the ignition switch, my demon problem. Thank you for helping me. # 16 is on the bottom of my bulkhead connector, but in the manual, all the connections look upside down.