Will I hurt the value of originality.

If you're rewring the whole car, Or the 6V harness needs significant repair - you dont trust it and chasing issues, its a good time to move to 12V. I see new wiring 6 or 12V as an improvement that would help value if thats a major concern.

Are you planning on selling the car soon? If Not, do anything you want to it. Its just metal, paint, upholstery. Literally anything can be undone on that car.

Mustang 2, no way. Id front clip it with a late model before I did a mustang 2. Front clips and mustang 2's get no love in these parts.
Only reason not to rebuild the existing front end and upgrade to discs if you want....is if you were doing a radical build to race, or slam on bags, etc.

 

I believe the original poster is long gone... gotta have thick skin to hang out here. He should have just read the posts, most guys said the same thing; make it yours...

 

And most of us think that was a high price.And if that was a comparable tri five chevy it would sell for 5 or ten times that amount. I havent any use for original or matching numbers stuff.

 

Todays 6 volt batterys are poor quality. back in the day many used a 8 volt battery and adjusted the voltage regulator. My father had a flatbed with a flathead 8. On the cold northern Indiana winter mornings he built a fire under the oil pan. Carried the battery from the warm house and started it. The with a chain pull started all the neighbors vehicles.

 

The OP was on last at 9:00 last night. Maybe he's preparing a 2nd post.

 

Where do you find suckers like this, and why can't I find one when I have a car to sell?