Careful, this is life-safety equipment you're working with. It has to work
right, not just light up. Most of the "LED bulbs" on the market (including everything SuperBright sells) are unsafe junk that lights up but doesn't work
properly (right amounts of light through the right range of angles for your car's lights to convey their message to other drivers). Please see my detailed discussion of the matter
here .
Clean the front park/turn and rear brake/tail/turn lamp lenses in hot soapy water. If the reflectors are at all dull or peeling, stuff wads of masking tape in the bulb holes (or remove the sockets if they're the removable type), clean the reflectors with alcohol, then spray them with readily available "chrome" spray paint, which is practically ideal for the task.
Then, Put
these in the brake/tail lights and
these in the back-up lights. You will need to install
this turn signal flasher (2-prong like original, attach its ground wire conveniently nearby). There is no LED bulb that will work effectively and safely in the type of front turn signal lamps you have on your Dart.
LED headlamps: Yep, you can have them. Here again, there's a ton of unsafe junk on the market, but you've got a variety of legitimate options, too. One particular kind of junk bears mention so you know to steer clear of it, that is the "LED bulb conversions" now flooding the market claiming to convert halogen headlamps. They are not a legitimate, safe, effective, or legal product. The failure is at the concept level, not the implementation level. These are a fraudulent scam. Not capable of producing even a fraction of the amount of light produced by the filament bulb they supposedly replace, let alone producing it in the right pattern for the lamp's optics to work.
But there's a growing number of engineered LED headlamps on the market -- they range in quality and performance from pathetic to excellent. The
701C from Peterson is good (also rebranded as Sylvania Zevo). The
Truck-Lite unit is good (also rebranded as GE and as Philips). By a big, big margin the king daddy of them all is the 8700 Evolution 2 from JW Speaker in
chrome or in
black. But it's expensive and some people don't like its looks, so you have to decide that for yourself.
The best part: all these good LED headlamps I just linked are made in America!