Since you're dealing with some pretty sophisticated 3-axis trigonometry on that steering system, some alignment shops don't have enough theoretical knowledge to spot a potential problem, especially with a modified system. With the wheels pointed straight ahead, both the Pitman arm and the idler arm should be parallel with the frame rails. This makes a perfect rectangle with the Pitman, the idler, and the relay rod. The relay rod also must be parallel with the shop floor. The distance from the inner tie rod pivot on the relay rod to the steering arms should be virtually identical side to side. The inner tie rod pivot points should be almost even with the lower control arm pivots, or at least the same distance away from each side.
When the steering is at full travel both directions, the toe-out should be equal. The "Ackerman" angle is a theoretical figure which establishes the turning radius for each wheel. That's why the inner wheel on a turn needs to toe out, to keep both front wheels turning on the correct radius to prevent them from fighting each other in a full-lock turn and scrubbing the tread off. On the race cars, where we would often bend steering arms from rubbing wheels with each other on the dirt track, we had a set of Ackerman lines drawn across the floor of the shop, and we'd bend the steering arms back into place until the Ackerman angles were back into specification.
Most of that kind of geometry is beyond the capability of anything but a race car alignment specialist. Do you have a pro race team in your area? (NASCAR, not drag race!)
Jerry
