If you are sure that turning the key on is what caused "the smoke" then it is something which the key supplies and which is NOT fused. This includes the "run" wire feeding under the hood to ignition and the regulator
We saw 12 volts at the bulkhead connector with the connector disconnected, plugged in the connector, turned the key all the way to start, and then off once the link burned out.
I've got cheapo GM style ready to run HEI distributor on it
