70 and a 74 suspension

We continue on our project swapping the slant six K member out of the 1970 Dart and installing the V8 K member from the 1974 Special Edition Dart and the 318. I was about to order a suspension kit and realized I had just replaced the idler arm and pitman arm on the slant six suspension. I've looked and it appears as though the part numbers are different from one year to the other.

Am I wrong?
Can I use the power steering box from the slant six 1970 K member? (The one from the 1974 is leaking a bit)

Thank you!