Every 3/16 inch (4.7mm) the upper ball joints are moved rearward should increase positive caster by 1°.
The tires were shoved forward in the wheel wells when Ford modified the upper control arms. To the point some cars experience rubbing in the forward portion of the wheel opening. Moving the lower control arms forward shall serve to make things worse. Moving the upper control arms or ball joints rearward shall serve to properly center the tires in the fender openings and improve clearance issues.
There are several folks available to modify the upper control arms, that's the best way to accomplish this. I like "best ways".
Check out the topic at this link:
Sticky #2: Increasing Front Suspension Caster
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