Timing Pulleys - Camshaft?

Most overhead cam engines today use timing belts. This should
provide a cheap source for 2:1 timing pulleys. Do any of you know if
they are standard profiles? They would be a great solution with just
a little hub work if you could get the right size belts. I don't
think you can shorten / splice a fiberglass backed timing belts.

I freaked when I saw the price of pulleys for my mill's knee axis.
More than the motor, encoder and Gecko combined. If camshaft pulleys
won't work I will cut my own.

Roger S.