Reply to "More on Front Caster"

The max caster a '71-'89 Pantera can get is about 2.6 degrees positive (tilted back towards the cabin). For comparison, '70s Corvettes ran 7 degrees. And don't be surprised if your right side caster is a bit different than the left, as the front subframes relax. For caster modifications, I suggest you first install offset upper a-arm bushings in place of the symmetrical stockers. This changes max caster to around 4 degrees and does not require new shims. Adding offset LOWER a-arm bushings along with offset uppers increases the max possible caster to around 5-1/2 degrees. Milling 0.060" off one side of the upper ball joint carrier adds about 1 more degree and requires fabricating an extra 0.060 shim. Milling more than about .060 risks falling into the balljoint grease cavity on some cars, so be cautious here. Cutting the upper a-arms avoids all the bushing replacements and milling, for the same increases.
Parking and very low-speed maneuvers with extra caster does take more effort, but above walking speeds, steering effort is about the same. As a rule of thumb, the wider the front tires, the more vital extra caster is; some GT-5 cars are almost undriveable with stock alignment.
In '06 and '07, the POCA newsletter had multiple articles, with photos, on understanding and modifying all the various alignment parameters front and rear, including installation of racing ball joints and tierod ends.