Something else.........cannot tell from your photo but having the rear of the car up in the air "substantially" does not help handling.
As posted, more caster......the "go to" specs are in this article for modern radial tires:
Turn of the screw: front end alignment for performance on classic Mopars
Go down that page look for the "skosh chart"
View attachment 1715135211
Folks have already mentioned the "pump it down" article on power steering pressure
Pump It Down....EASY
Should be the pdf "I think"
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjMoPLlqvvYAhVF42MKHWNADAEQFgg1MAE&url=https://www.forabodiesonly.com/mopar/attachments/pump_it_down-re-v1-4-pdf.1714942218/&usg=AOvVaw3bv7eorFEvSPH5tMueD8ek
My Dart before we tore it down, steered GREAT. You want minimum V8 T bars OR BIGGER, some sort of anti-sway bar, and decent rear springs. I "budget built" my rear springs.....took apart the stock 67 spring pack, and a set out of a "junker." Used the longest leafs out of both sets to create one pack with one more leaf. That was a "trial run" but it worked out GREAT. The steering on the car is responsive and "certain" and goes where you point it.
"Generally" you want.........
offset top A arm bushings.......
All the caster you can get in it, then adjust the camber, while trying to leave the most caster "in."