ok, here's the link for the polarizing procedure to convert to Negative Ground:
https://starautoelectric.com/Technical.htm
An obvious benefit after converting to Neg. Ground that nobody has mentioned is: jumping the battery in an emergency. You can't jump from one car to another if the good battery is Negative Ground and the dead battery is Positive Ground.
I converted my '65 Jaguar S type to Negative Ground following Mike's instructions after I asked him about the conversion procedure found at the Jaguar Club of North America's website which incorrectly stated that: "the Terminals at the Generator should be shorted and that re-polarizes the Generator from Positive to Negative Ground".
Mike told me "don't do THAT! you will smoke your generator".
He sent me instructions on how to do it at the Voltage Regulator, which I did. He also insisted that a new battery should be installed, which I also did. Mike knows his stuff, he makes a living at rebuilding Lucas. The conversion was succesful and I am of the opinion that all the electronics in my car are more "lively" after converting. don't ask me why, I don't know, but the lights are brighter, the car starts faster, period. Yes, I had to invert the Coil wires, and the Ammeter Wires. Everything else stays the same and I installed a modern stereo without any worries.
Positive Ground may have been fine up to the 1960's, but in modern times, I don't want to be worrying about which of my two Jaguars is Positive or Negative ground, since all cars are Negative Ground nowadays. Today they are both Negative Ground.
good luck -
Ex