Tire discounters can’t align my Dart.

Bethel Frame is the way to go. I wish you'd have dropped me a PM first before going to Tire Discounters.
They (Amelia, Cherry Grove and Eastgate) used to send work to us because they couldn't handle anything older than 25 years.
Our alignment machine was only a couple years old, but we could take manual adjustments and load the measurements into the heads.
Greg out at Bethel Frame will do you a good job. I know he's back logged with work.
If he's to far out on the schedule, call Georgetown Tire and Service. Tell Denny you only want Jim doing any work. Jim used to work for me and knows Mopars like the back of his hand.
Southside does good work as well. I've never had an issue with them. Gary can get a little wound up, but I'm thinking he's not at the shop as much and Eric is running things.
Both places know cars. They know what they're doing and will stand behind it.