More on Front Caster

I've had my upper A-arm modified which resulted in the ball joint being move rearward approx. .75". The car tracks beautifully but at very low speeds there is a bit more effort. It is well worth the modification.
Mark
5481
5461

I completed this modification and it takes a little bravado to cut up you A-arms, but is a surprisingly easy mod for anyone with access to a MIG welder and press. I gained exactly 3/4" rearward shift in the ball joint. I also welded in my own camber locks.

Thanks for the replies. The affect of more caster is appreciated and understood.

Just wanted to know if there was any noticeable change in the position of the wheel (center of wheel goes 3/8" rearward) in the wheel well or clearance issues induced by the mod. Sort of depends on front wheel size and ride height.

I have 265/35/ZR18 front, fairly low ride height for the street, and steel GTS flares. Could increase ride height if necessary but am pretty tight clearancewise as it currently sits. The flares were hung the centered on the wheels. Suppose in theory you could move top ball joint 3/8" rearward and bottom 3/8" forward to achieve same result but a lot more work to mod lower A-Arm too, especially if not necessary. -Probably overthinking this.

Kelly

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.