Tire discounters can’t align my Dart.

Hate to say it but Tire Discounters isn't on my list of places to take a vintage vehicle... Not saying what you got is right but I wouldn't expect them to have a clue on how to set up your alignment...

If you were local I'd introduce you to my guy.. He's been doing alignments since before your car was built, took over his dads business that his dad opened in 1946... He played with muscle cars when he was younger & his thing was tweaking the alignment & suspension to go round corners quicker... So he knows what does what & why....

There is probably someone like him near you, your job is to find that guy.... Cause all the new parts don't do anything till they are set up right...