I have an st170 inlet manifold. but i was wondering what the spindle, sticking out of the end, does? as its got a large internal butterfly attached to it!???

at first i thought it was the throttle butterfly, but thats on the throttle body.

so, what is it? is it to do with the st's torque restrictor?

And.. . what do i do with it on a zetec engine?!