One of the things the Ignition switch does is supply hot to coil. The switch gets an almost direct feed of 12V to it's BAT terminal, then when in Run/On it energizes the On terminal/wire to the Ballast, then thru ballast and to coil pos. There is another wire from coil pos to solenoid R. There is a wire from solenoid S to Start terminal on Ign Switch. To repeat: There are two wires on the coil pos.
You have it wired wrong so that you have hot to coil somehow, but it's not switched by the On Terminal as my above.
When the solenoid is energized it starts the starter motor AND it supplies hot from R to coil during start. When you let off of key, the R is disconnected and the hot from ballast (which is wired from the ON position on Ign SW) takes over to run the motor on less than 12V to points.
As you mentioned, FORGET the colors and wire start/run per schematic or my info. The other ACC stuff/Ammeter is up to you.
If your ignition switch is not marked and you don't have a diagram of what terminal is which, you will have to take switch out and test continuity and find out what each terminal is for and write it down on a piece of paper. You just have to chase each wire as it comes out of the switch connector and be sure you know what it is and where it should go.
This problem is normal and you are normal. Just redo the think.
This is all assuming you have a solenoid on your starter and by V8 switch you mean the spring loaded/momentary/key to the right to start.. style ignition switch.
I would also like to know what Mike is asking. We can't tell you what any wire is for from our house. You said the PO may have changed colors and obviously something is wired wrong. If we guess at that it could cause you big problems. You will have to determine the whole ignition switch wiring.
