Ammeter discharge with key on

I've been chasing an electrical problem for a few weeks and trying to get the car roadworthy for an alignment this weekend. The car is a 74 Duster that I bought last year that had been mostly disassembled, so I'm working with a basically unknown car.

Here are the symptoms, maybe you guys could give me some ideas on what to check next...

With the key turned to ON and no accessories turned on, the ammeter shows a significant discharge...about 1/3rd of the way to the first discharge mark, which is about as low as I'd expect it to drop when cranking the engine.

I disconnected the ground from the negative post on the battery and put a test light in there so I could see what was going on. Key ON, bright light. So I went through and disconnected all of the fuses..key ON, bright light.

I replaced the starter last night with a known good one because it had a dead spot anyway, but that didn't make any difference. I remember when I was fighting to get it fired the first time, I checked the voltage at the coil and I was getting about 4 volts run/6 volts start.

Where do I go from here? I have grounds from the battery to the engine and battery to the chassis, but can put in more if it might help. Any help would be greatly appreciated.