Steering shaft diameter
The big block dart link suggests at the end that a manual big sector van box might facilitate a move from power to manual steering on a big sector car.
i belive that vans used a more of a "Cab Over" set up with a reversed linkage.
Basically every chrysler commerical vehicle wormscrew and ballnut i have seen has its thread cut reverse to what you need in a standard car.
that doesn't mean all of them are like that, but my investigations into cheap 16:1 ratio updates lead me to van wormscrews which were the right ratio, in many cases of managebale length at the spline, but wrong thread orientation
In which case the conversion would have had the wheels turn right when the steering wheel was turned left and vice versa great for clowns, not good for the rest of us
obvioulsy you have no such problem with sector shafts. you just need a manual or a power one for a car or a truck, and in the correct size for you case and pitman.
Dave