Think all would agree that in 66 era cars incandescent headlights were not very good considering the LED headlight performance of todays cars. After research and some posts on various forums about folks that did conversions to various other brands of LED headlamps that required either some mechanical or electrical modifications, I decided on "Holley brand Retro Brights". A bit pricey, but they are truly plug N play with no modifications or messing around required as with other less expensive alternatives. Installed them yesterday on my 66 Charger and very pleased with them. They draw a lot less current that the original incandescents and light output is significantly better as one would expect..