1969 dodge dart pitman arm

Take a look at your center link- if the tie rod ends, pitman and idler arm studs install downward through the center link, then someone installed '73 and up steering components in your car. '72 and earlier cars had components that installed upwards through the center link.
Count the splines on your steering box output to make sure the count is correct on the pitman arm you order, some listings are inaccurate.
When counting the splines, you will notice that there is a "gap" at one point- this is called the "master spline" and is used to correctly index the pitman arm. When counting, pretend there is an additional spline (or splines, I forget how wide the gap is- I *think* it's just 1 spline) and include that in your count.