Mebbe if u explain to them how much you love your darts, mebbe they would be willing to apply some money towards rehabbing one of these. New paint, carpet, upholstery, rechrome bumpers, mebbe a nice new V8, some wheels, and go thru all its working systems to make sure its reliable and safe. This is a win win for all of you.
You get one of your cars all fixed up nice as a daily driver. So now you got a classic car thats really nice looking and ur parents feel a bit better about you driving an older car as long as everything has been gone thru and is safe.
Think of it as the automotive equivalent of what we do in my industry with aircraft. We do whats called a heavy check or D check. Airplane up on jacks, and pull it apart. Inspect and replace all worn or questionable parts is a major part of a heavy check, theres other aspects of it as well. Structural repair work goes on too.
Think of all the mechanical parts on your dart like your doing a heavy check. Put it on jacks, go thru all the suspension parts, change out the brakelines and components for new parts, upgrade everything at this time. Go thru engine, transmission, wiring etc. inspect/replace everything thats worn, or questionable. Replace rusty floorpans etc. Lots of repop parts for darts out there now so it shouldent be too hard.
Come up with a gameplan and show it to your folks about how you would rather rehab one of the darts to make it reliable. Ask dad to help you so you can get it done quicker with extra help. They will appreciate your honesty, mebbe u can sweet talk em into a crate 360 from mopar performance for this. Its a new reliable engine ;)
If all else fails, sweet talk em into a new challenger, tell em u like the way those look better