Searching for 12v switched power after ditching ballast and installing aftermarket electronic ignition
What I'm saying is that it sounds like the start wire from the igntion switch controls the relay
When the relay closes, power goes from the battery feed on the relay to the starter solenoid and to the ignition start wire.
Up through '76 for A-bodies, the relay does not have the BAL terminal. The EGR was connected to the SOL terminal so functionally that's the same.