This project started when another Mopar owner told me that he'd had a recently bought voltage regulator die on him, and found it had been filled with sand under the potting compound instead of fully potted. I bought a cheap stock replacement regulator to inspect, and found there were a lot of shortcuts besides just filling them with sand - the temperature compensation was missing, the components had 5% tolerances (and these could stack up, so theoretically your charging voltage could be off by more than 5%!), and all around it was clear they had been trying to cut costs over building it soundly. I could tell that I could build a better regulator on my kitchen table. So I will.
The temperature dependent feature serves two purposes. One, batteries can't charge as fast or handle as much voltage when their temperature comes up. Two, it can reduce the odds of overcharging, although with lead-acid batteries the odds are pretty low you'll overcharge anyway.
Other than the direct battery measurement circuit, this is more or less the OEM design re-created with good quality parts that are widely available now, and quite likely a bit more current capacity for the field coil. I tested a more complex version that used a microcontroller, and found that unless you wanted to add features like a current meter and custom battery profiles, it wasn't really an improvement over the stock design.
The stock 1964 alternator isn't going to work, but you may want to check if someone's swapped in a later design. They could be using a dual field alternator with the second field terminal grounded.
I'll have some pictures together once I build up these circuit boards.
