So we ordered the wiring harness required off of ebay, and a new alternator off of Amazon.
One tricky part of this upgrade, was that we would have to replace the serpentine pulley from the modern alternator with the original v-belt pulley from the classic Mustang. We would love to upgrade to a modern serpentine pulley system as well, but that would require replacing the water pump pulley, and the crankshaft/balancer pulley. We have not been able to find suitable replacements so far, and the upgrade kits for this are in the $300 and up price range. We'll just keep it classic for that price.

Once we got that in place, it was time to install the new alternator.
Here we are, all installed with the v-belt pulley.
Once that was done, we wired up the alternator. 1 Wire in this case, really means 2 wires. 1 wire to the ignition to turn on the alternator coils, and 1 wire to connect the output to the battery. We used some jumper cable wire, and a few good solid connectors and wired this up to the battery, and then on to the starter solenoid for a nice clean and heavy gauge connection.
I can't even count the number of wires that were involved in the old system. 3 at the alternator, a handful at the external regulator, and the output was run through the dash to give a Charge/Discharge gauge readout. We'll replace the Charge/Discharge with something else later, perhaps a 10-16V gauge. At rest, the system is roughly 12V, when the alternator is on, it's somewhere around 13V. If the engine is running and the alternator is not functional, the voltage is somewhere around 11V.




















