I say keep it *mostly* original.
1 - get a modern flamethrower or whatever it's called point system. Keep the original of course in case it ever gets sold or passed on.
2 - Do upgrade the brakes to modern equipment if possible. Tires as well. Again, originals in a box carefully stored somewhere. Even modern drum brakes are far better than the originals.
3 - Do upgrade the wiring to the headlights and so on as well as obvious stuff like seat belts and more modern speakers and so on(obviously keep it 100% stock look of course)
These make great cars to restore.