I'm in the process of converting to floor shift in my '71. My question has to do with the lever at the end of the tailshaft on the floor shift column I purchased.

I can't figure out why you would need this lever on a floor shift car. It makes sense for column shift cars, since this lever connects to the shifter linkage and changes the gears on the trans. It can't be for the neutral safety switch, since floor shift cars have this switch in the shifter.

Why do floor shift cars need the steering column collar to rotate (via the steering column lever)?

you hook it up so when the car is put in park and you turn the key off and pull it out, it locks the console shifter in park and you cant move the shifter until you turn the key. jim