Harmonic Balencer & Pulley Alignment

There will be a slot in the crankshaft with a "key" in it and a matching slot in the hub of the balancer.

Caradiodoc

OHHH! The pulley doesn't matter. Most vibration dampers are simply a heavy metal ring mounted on rubber sandwiched between the the hub. It's position is not important but a key way is used to prevent the hub from spinning on the crankshaft. Once that happens just a little, the metal parts will start to grind down and it will continue to loosen at a faster rate.

Some manufacturers use an "externally balanced" crankshaft. That is more common with cast cranks vs. Forged ones. It is difficult to cast some of the counterweights so instead they put one of the weights on the vibration damper and one on the flywheel or torque converter. For those the key way is doubly important to insure that weight is in the right location.

Pulleys made from stamped steel will not have a weight added to them. There are some pulleys that are cast onto a steel plate and could have weight added to them. When you have that style there will be one of the mounting holes that is offset if it has six mounting bolts. There could also be a key way slot in the pulley's mounting plate but I don't recall ever seeing one like that on a car engine. If you have six mounting bolt holes and they all line up with the holes in the damper, you can mount it in any position.

Caradiodoc