My 72 has 73 HL Switch adapted, but I believe it still pulled off the Shaft. If in doubt, pull switch out to on Position ,then using 90 degree needle nose pliers grab the shaft behind the knob to take the stress off the switch assy internally, Then pull straight out , holding the shaft still so the switch internals aren't damaged. If you still see no movement, and that doesn't release, Stop then look for a retaining pin at the knob base. As old as the plastic is, be careful it doesn't break into pieces. Some German cars (Vw for instance) have a Button to be pushed in the back of the Switch and the whole shaft and Knob pop out in one piece.
 If you have no success, stop and rethink how you approach this, nothing more disappointing than having broken parts in your hand.
 
Pintosopher  A Knob would never get the Lights on in this Mind

I was just E-bay and someone had the switches and the knobs for sale. Put in ford pinto knobs and they should pop right up!