Chrysler made two steering column adapters that looked similar. One was for putting a rimblow or Tuff Wheel on a A-body or B-body early 70’s. The other one was for later 70’s like Cordoba, Magnum, Little Red Express. The later one has a smaller diameter spline which is probably what you have. It will not fit on the E-body column shaft.
Dales Cuda Shop and Classic Industries has the one you need, new and already painted black.