I did some alignments when I turned wrenches back in the late 70s. I would cringe when a Mopar or Ford for that matter would come in. They both used similar eccentric type adjustments. The trouble is keeping one eccentric from moving when you have to loosen both to make certain adjustments. Its been over 30 years since I had to do it but I remember them being a nightmare. Least for me. It was one of the few things GM had going for them IMHO. Just loosen the UCA mounts and install or remove the right combination of shims and re tighten. Piece of cake