Losing switched power and other #$%&^# electrical issues. HELP!

I need some help. My 73 Dart Sport, 408 stroker / 200 4R, has been running great for 6 years. A month or so I came home from a car show and it would not shut off. Key turned off, key in hand, but it stayed running. I didn't notice it before, but I drove it a week later and noticed it wasn't charging as well. It seemed like it was the ignition switch, so I installed a brand new one. Same issue. I had 12.6v at the battery and only 10.8 at the alternator. I started tracing the power to the alternator and after a little checking I found the car wouldn't start. The MSD ignition wasn't supplying power to the coil. I had constant power and ground, but I found the switched power to the MSD had 12v key on, but lost all power during cranking. If I added 12V to the switched line the car starts. I draw the switched power from the ballast resistor, and have since I put the motor in. I have key on power at all four terminals but lose power to all four when cranking. It seems to me that my new ignition switch is bad, but I am looking for opinions, ideas, etc. When I ran power to the MSD box and got it running today it still wouldn't turn off with the key and was not charging. I have to believe they are all related and that in the end one repair will fix all the issues. HELP!