69 notchback questions

Sweet car! I know notches had less production numbers than fastbacks, but they aren't worth as much for some reason. I'm not a big 'keep it all original!' guy, but how that thing looks, and it's a 340 numbers matching car, I'd try to keep it original. (Maybe different drivetrain to horse around in, but keep all the original stuff so you can turn it back to original if you want to in the future).