'71 Swinger! Like it or Not

The stripe should end on the body line, there should be no stripe on the valance panel. When done correctly, you can stand behind the car and see no stripe. Then standing at the side of the car, see the stripe all the way down but can't see it end. So from a side view it should look as tho the stripe wraps right under, but it don't

Yes, there is a stripe on the valance if done correctly. This is an actual Dodge publicity photo provided by Allpar.com. You can clearly see the stripe continues onto the wraparound portion of the rear valance, and terminates just past the lower rear body line:

http://i1286.photobucket.com/albums/a611/MPR_Chassis/dart-swinger_zps8ef69641.jpg

Also...out of curiosity I checked out the pics of your Dart (very nice car btw), and you have the stripe on the rear valance. So now I'm a bit confused how you could think it's not correct to do so.