tie rod question a body

I have no idea why a 75 Dart tie rod end would have a different part number from 68 Barracuda.
Like said above, even C-body tie rod ends with larger threaded stems use the same size/taper ball stud. So to negate the questions, just order 68 barracuda tie rod ends. You know those match your center link, adjust sleeves, etc... and we know they fit the 75 Dart spindle hole.