Being an alignment technician I have set up an A body Mopar or three over the years..............
One potential 'snakebite' that many folks are not aware of is the centering valve on top of a power steering gear.........if it is offcenter one way the car will go right, if offcenter the other way, vehicle pulls left. It is easy enought to adjust; just loosen the 1/2" bolt heads and gently tap the valve one way or the other then tighten things back down. :)
Needless to say: we are assuming that the alignment is dead nuts and that the tires are OK as in no radial pulls.