[Thomas]

It may not be a distributor problem. I had to change to high torque mini starter on my L78 Camaro this summer because the headers and cowl induction air cleaner were overheating the solenoid. The mini starter did not have the 2 small lugs for the 2 wires that the original starter had. When I spoke to the perofrmance shop where I bought the starter, they suggested connecting both wires to the single lug on the starter. Remember we are not talking about the positive battery cable here. This didn't work. The car would start but as soon as I release the key, the engine would stop.
What I learned was that the one wire only provided full battery voltage to the coil to make sure it had enough power to fire the spark plugs on a cold engine. This wire is only hot in the Start postion. The other wire is hot in the run position. It could be that this wire is broken somewhere.
I'm not sure whether this will help, but you may want to look at that.

Thomas