Below are a couple of
links that show some examples of how to rewire generator systems to internal reg alternators. The first rewires a Buick with generator and a Buick with external reg alternator. It also provides a lot of additional info and
links.
http://www.rowand.net/Shop/Tech/GeneratorToInternallyRegulatedAlternator.htmThis second one is for Corvairs, but they use the same generator, same regulator and the same wiring if your '58 Apache has a generator (idiot) light. Generator conversion on top and ex-reg Alt conversion on the bottom.
http://autoxer.skiblack.com/nallm/ireg.jpgIf your truck has an idiot light, it will be wired very much like the drawing in the top, left. In the middle of that drawing, is a plug called a "main harness connector". The wire from "A"( or "GEN") on the regulator goes through that plug to the "GEN" light in the dash. The other side of the "GEN" light goes to 12 volts when the ignition switch is switched "ON". From the ignition switch, it is connected back through the "main harness connector" to the "Bat" post on the regulator.
From the second drawing in the first link, I would like to point out a couple of things.
http://www.rowand.net/Shop/Tech/images/AlternatorWiringSchematic-1974Buick.jpg In the lower right you will see a wire labeled "24 brown/white (resistor wire (10 ohms)". This resistor is in the wiring harness for vehicles with the 10DN External Reg Alternator and the 10SI or 12SI Internal Reg Alternators. This resistor is in parallel with the "GEN" lamp when the ign key is "ON". It is there so that if the "GEN" lamp should fail, the circuit will still be complete. You do not need it, BUT a 10 ohm 10 watt resistor from Radio Shack wired in parallel (across) the "GEN" lamp will do the trick. I think it should be included, but most people don't bother.
This "GEN" lamp connects to post #1 on the Alt and it is the Exciter circuit.
On the top left of that drawing you will see a "10 Black/red" wire that connects #2 on the Alt plug almost directly to the Batt post on the Alt. This is the "Voltage Sensing wire" for the voltage regulator. If you have read the MadElectric web page, he explains in detail why this is not the best place to connect the sensing wire. In the next drawing you can see that the "Sensing wire" is connected closer to the battery, where it should be.
http://www.rowand.net/Shop/Tech/images/MergedWiring-1958Buick-InternallyRegulated.jpgWaldo was totally correct, about the residual magnetism. Take another look at post #1 in the drawing. Internally the post #1 connects to the voltage regulator then the field. Also connected to #1 internally is the feed-back circuit from the diode trio. As was pointed out, the residual magnetism is minimal, but if you rev the snot out of the engine the stator can generate enough voltage through the diode trio to do what the Exciter circuit is supposed to do in the event you don't have it connected properly.
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml does a great job of explaining all of this and a lot better than I ever could.
