You should probably upgrade the linkage at the same time. I am not sure if there is a tie rod end to mate the new box to the old linkage. There is an end to mate the new linkage to the old style box though. The pitman arm has to be changed as the new box has a much larger sector shaft.
Given the cost and having to upgrade the linkage, the fact that you probably will have to upgrade the pump, and some of the weird issues with the new box, you might want to consider a Borgeson or Redhead steering box. The new box is a beefy monster but if you don't need it it may not be worth the cost of it and the other requirments. The box itself is over $600, linkage is around $300, and a new PS pump is over $300 buying wholesale.
A replacement Borgeson or Redhead will run $400-500. You choice.