Massive caster variance Side to side
Check the strut rod bushings on each side. Are they the same type? There are various rubber replacement ones. If someone replaced one side it may not have matched the other.
Also there are two lengths of strut rods. One for 67-72 K-members and another for 73-76. Maybe they are mixed?
I put a B-body strut rod on my 68 Barracuda once to replaced worn out threads. That was WAY off! And they look close... until you measure shoulder edge to shoulder edge.
I'm sorta surprised you only got 1 deg gain by putting in the moog 7103 offset UCA bushings. Did you install them like this?