several voltage regulator burn

It's a argentine Chrysler car, a Dodge GTX 1970 with a early a-body. the electrical circuit was old, no electronic ignition no electronic VR.
I connected the Holley EFI directly to the battery with a circuit separate from the car. The original circuit only handles the alt/VR, starter, lights, dash. The EFI circuit handles the ECU, fuel pump, coils, radiator fan.
Run a wire form battery gnd to VR chasis, I checked the voltage drop between the negative terminal of the battery and the chassis, block, alt, vr... all ok