Fully adjustable upper A-arms for ‘67 Barracuda

Hotchkis makes a small ball joint version of their arms, #1112-S

They have heims though, which you may not want for the street. And they’re only single adjustable, you have to pull them out of the UCA mounts to adjust the UCA itself.

QA1 also makes a small ball joint tubular UCA, but they’re not adjustable. They do have additional caster already built in though.
jeebus! $450 for the QA1's (plus $65 for their eccentric bolts) for 3 degrees of caster! for $300 mas at least you get adjustable with the hotchkis, even if you have to take them off (makes face).