Such a pisser.
When these cars are lowered and have big tires, there is not much room to work without lifting it up to let the tires droop a little. An experienced tech, one with experience with these cars, should know what effect a hanging suspension has on the camber and caster.
Example: If the car has to be lifted to gain access to the upper control arm cams, he should know that raising it (with the tires hanging) will add X amount of caster, X of caster. A setting can be made with that in mind, then rechecked with the car back on its own weight. Toe can be set easily with the car at any height.
Most of my experience is with A-Body cars but the suspension and steering is the same. If you lift the car up, the "track" of the front wheels narrows. "Track" is the width across both front tires. Some magazines measured it from center to center. As the front suspension extends, it gets narrower as the control arms move away from the resting position. Once you lower the car back onto the tires, there is usually a sort of "bind" in the suspension that results in some positive camber and toe in until you move the car back and forth a little bit.
In the late 90s I was making a home movie with car stunts, wrecks and off road bashing. I used a 73 Duster, a 74 Dart Sport, a 75 Dart 4 door and a 76 Dart. I bent lots of control arms, damaged K members and shredded some bushings. Sometimes the K member is damaged where the lower control arm shaft is mounted. In stock form, it is not too beefy and the welds can break. I've seen neglected, high mileage cars with NO remaining strut rod bushings, egged out LCA mounts in the K member and LCA bushings shredded. Some of the damage is not immediately evident and requires a teardown to find.
A few years ago I had my Charger on jackstands to look at a few things and saw that my 12,000 mile LCA bushings were coming apart. I like to think that during the front end rebuild in 2003 that I was smart enough to tighten the LCA shaft nut with the car on the tires but I can't be sure. I may have tightened it with the tires hanging.
I have never worn tires that bad, that fast. Something is wrong, especially if the camber appears normal.
My specs for my alignment:
Camber: .75 Degree NEGative
Caster: 4.5 Degrees POSitive
Toe: 1/8" toe IN.