I have a 1964 Mark X 3.8.
I've never worked on this type of car before.
I've heard the polarity is different on these cars, is that accurate?
If so, can it be changed to negative ground?
If changed to negative ground, does absolutely everything need to be changed out of the car- like power windows and such?
The car is getting a Chevy 350 motor.

 

I had a 1967 Mark 2 swapped to negative earth by an autoelectrician. It was almost a five minute job, but you have to swap over the leads on the ammeter so slightly more time.

 

Also, if your car is equipped with a radio, it too will have to be switched over to negative ground, or bad thinks can happen...

 

Hi Rugul8r,
Here is a procedure for switching from positive to negative ground. It came from the JCNA web site it covers the basics.

https://www.jcna.com/positive-negati...d-conversion-0

For the power window I would try it without swapping the leads, it should work. But the switches may work backwards.

Sorry to hear about the 350 swap, that's a lot more involved than a simple polarity change. But if that keeps/gets the car back on the road so people can enjoy it, so be it.

I had a friend who wanted to swap a Jaguar 6 cylinder engine in to a 36 Chevy just to prove a point. He never got around to it, RIP Gary, you're missed.