steering coupler replacement (how to)

Anybody know which of these (size/spline) I would use on a 69 Dart (pwr steering)? so I could order without having to take my column apart until I need to? Thanks...

this is the one I bought for my Dart with a power steering unit, I switched to a manual unit and its the same spline as well. Also I just checked my old power steering unit and its a 3/4 36 spline.


http://www.bryke.com/310-236/Steering+U+Joint.html