You mean gear, not pulley. Don't use excessive force. You can break out the spokes or hub of the gear. And you don't want to distort the teeth, or they'll make noise and damage the mating gear as well. I found mine was broken, but the hub slid off the camshaft and dowel pin fairly easily.
The older style gear and newer one don't interchange. You need the whole cam shaft as well. And then, there is possibly something about the thrust washer and front plate to worry about. The newer gears are wider as well. They also made service replacement gears with the 3 holes, but thicker. This indicates a problem area.