[rotorwrench]

Flatjack9 has a point that the degrees of spacing between the teeth on the gear isn't very much. No timing marks are needed there. It won't adversely affect distributor position much at all. The vacuum advance tube will still fit after the distributor is timed to align the crankshaft timing mark on #1 cylinder.

If any given tooth aligns with some reference mark on the cam then just align any tooth with that reference mark when installing the replacement gear. Make your own mark before removal of the old gear.