Led Lights
Reverse lights would be for a 67 Dart
These Sylvania Zevos will work at least reasonably well in the '67 Dart reversing lamps. The Philips ones with the LEDs in a sorta-filament position might work, too; have to try and see. The Philips ones with the three outward-facing panels of LEDs are junk in any lamp, as are the ones with the LED mounted flat on the bulb base (shooting straight out away from the base) with the diffuser bubble around them.
Paint the reflectors with Ceiling White paint (not just any old white paint; go to a paint store and get Ceiling White), which is practically ideal for the taskâyes, even if the original material on the reflector bowls was more of a silvery stuff. An example is 'Ceiling Bright White' from Sherwin-Williams; they'll mix it up for you as a polyurethane-based paint on request. It's water-based, so it won't stink up the place and it's easy to apply and clean up. Don't worry about the surface gloss (or not-gloss) of the ceiling white paint; surface gloss isn't the thing here. "Chrome" spray paint is a fairly decent second preference, but the white works better; it has 90-some-odd-percent reflectivity of incident light with broad diffusion; see
here for a demonstration; he takes awhile to get to the point, but he eventually (3:24) he starts to get around to it, and the difference is pretty obvious even with a low-quality camera. And he just used regular white, not ceiling white; regular white looks dishwater-grey next to ceiling white.