Hey Chris (mr lucky)

This one gave me a run for the money
It was the J2 DBL/W wire at the firewall bulkhead.We found a bad connection.The wire was not making good contact where the wire is crimped to the male blade terminal inside the 8 wire connector.The J2 goes from the Ignition switch to the bulkhead then feeds the Regulator which in turn feeds the resistor,coil,alt,and solenoid.
Hope this helps someone