66 Dart Steering Shaft

See if this helps. Rebuilding a 1964 Plymouth Steering Coupler Also 1966 dodge dart steering shaft breakdown-Google search.
FYI....be sure to note the position of the coupler on the steering shaft and reinstall it the same way. You can reinstall the coupler two different ways on the shaft and if you choose the wrong alignment, the steering wheel will be upside down. The missing spline on the upper shaft at the steering wheel has to match the missing spline on the coupler.