I believe that a steering box together with drop arms and drag links suit a Morgan's chassis and suspension design much better than a rack and pinion setup.
Chassis flexibility combined with the vertical sliding pillar (actually the stub axle moves not the pillar) means that bump steer is built into a rack and pinion setup whereas a steering box setup is much more tolerant of a Morgan's chassis characteristics.
Why did Morgan move to rack & pinion? Most probably fashion and without understanding chassis and suspension geometry. in addition, unavailability of supply.
