I found out the expensive way that some of the factory adapters don't fit our "A" body cars. Bought one that looked like an "A" body adapter, but wouldn't fit the spline of the steering column. Not sure what vehicle it came off, maybe a truck.
Ended up buying another from a member here that personally removed it from an "A" body and it fit and worked fine on a 72 Dart. If I remember correctly the "A" body one had a small notch in the spline of the adapter. The one that didn't fit had no notch in the that area.