Ignition just cuts out.

I'm seeing more and more guys with these old girls having troubles with mostly the bulkhead connector. I'd pull it apart, clean, and inspect.

Turn the key to run, engine off. Measure the "dark blue" ignition run supply line, either at the regulator or at the ballast resistor.

Make sure you are getting the bypass circuit. This is the brown wire going to the coil side of the ballast, should be same as battery voltage in "start." You should have at least 10.5V or more at the battery and at the brown (coil +) when cranking.

I had a tune - up guy claim that he thinks some of these pickups are losing magnetism. They aren't that expensive, would not hurt to change the picku and reluctor wheel.

ALSO pull loose the connectors on the regulator, the ECU, and the distributor and work them in/ out to scub them clean. Especially if the dist. connector seems at all loose, I'd pay particular attention to it.