yeah it should move.
take out the thermostate and watch. if it still doesn't move, you either have a plugged bottom of the rad, or some other blockage.

based on your post in the fan thread, I reiterate you have a blockage or restriction.
reving the motor puts a slug of cooled water from the rad into your motor, "dropping" temps that you can see.

it may not be the thermostate since you changed it, but something is restricting flow.

a/c pulleys require the full set of pulleys. you can't mix and match. Sorry wasn't thinking, or would have mentioned that before.

not only are diameters different, the off set will be different too.