From my past experience with modifying steering components, I suggest you bend the pitman arm (or find one that works) so it will keep the box centered and will meet where the drag link needs to be for it to be centered. Attempting to adjust the tie rod ends to accomplish the task creates more issues then it solves.

When do you think you will be moving forward with this swap? My son has a 57 Dodge with the original power steering, unfortunately, last summer the car went under water and we have concerns about the condition of the power steering unit. His car has a 5.7 Hemi, we had a pump modified to run the original power steering, and we will replace the pump, but it would be nice to upgrade the original power steering unit as well. Gene