Joined: Nov 2016
I know I've already been credited with a response here (thanks, Travis) but now I'll actually type one.
Cheap "restomods" using generic parts like Grant steering wheels, new gauges, aluminum radiators and aftermarket brakes (requiring larger wheels) are common, because people don't want to hunt down the real parts. Doing a fix-it like that would absolutely detract from the value of the car.
If on the other hand, you were to really think things through, and chose to upgrade to better shocks, stiffer sway bar, did the Shelby drop, put in a dual-bowl master cylinder, front Kelsey-Hayes style disc brakes, etc.
- in short, upgrade things just a bit in order to make the car safer to drive, while maintaining easy-to-find factory type parts that don't look out of place -
I think the value of the car would be *increased*. You obviously have to do repairs, which means that 100% untouched original is off the table anyway. Putting a roller cam in your engine is a good example of the type of thinking I'm talking about. You can't see it, and it does not greatly change the character of the car, but it would let you run modern oils and drive without worrying about tearing a lobe or two off your flat-tappet cam.
Given what the car is, I do think it would be a mistake to put modern wheels and low-profile tires on it, or to carve out the dash and put in a DIN chassis digital radio. Besides, there are ways to upgrade your original radio and give it fantastic stereo sound these days, with AM/FM/Bluetooth/USB to boot.
If you are conservative in your approach, but ensure that mechanically it's more sound, and the changes you make could be un-done by a rabid restorationist, then I think you'd be on the right track.
I smile a lot. It makes people wonder what I'm up to...