Where to get the little light bulbs

No changes to circuitry. They fit just like the regular incandescent bulbs. The dimmer works the same.

I should add that I never drove this car before the upgrades, so can't compare to regular bulbs other than my 65 Newport's dash or what I remember from my 69 Dart. So far, I have only driven the 65 Dart once - to the DMV. But, I was pleasantly surprised when I tried the LED dash lights. I had taken apart the dash and polished the plastic lenses, so that surely helped. The main reason for LED's was "should last forever". I'll know in 10 years.