which center/drag link am I looking for?

THIS!!^^
..........And of course remember the pitman has to fit whatever spline your steering box has......
Early: up through 72

View attachment 1715981527

Late: 73/ later

View attachment 1715981528

And if you need a 73+ style pitman for a small sector power steering box, you’ll need to buy a pitman for a ‘73+ manual steering box. Because unless something has changed none of the parts descriptions will match a small sector power steering box with a 73+ pitman. But it fits, I have the 73+ manual pitman on the small sector power steering box in my ‘71 Dart with the 73+ center link and idler. With the ‘71 K for that matter.

The ‘73+ power steering idlers will be for a large sector power steering box.