New alternator, 4 regulators, still can't find voltage draw

[ggucci3]

1973 chev g10, just replaced the alternator and regulator again. There is a current draw somewhere in the charging system, just cannot find where. The system charges at 17-18volts, so i'm burning through regulators. key off, the battery shows 4 amps draw; when I disconnected the regulator, the draw goes to 0. Any ideas??