Help With Instrument Cluster

Not sure how the knob comes off but all of the ones pictured above are rally dashes. The standard ones from the 70's are about half of the width and have a square opening for the speedo, no tach, and little round openings for the "other" gauges. The standard A-body ones from the late 60's look like this:


Thanks red for the correction, the one in this pic is out of a dart or something (I think??)