how to tell if the distributor drive gear is installed correctly?

Newbomb Turk said
This is ONLY and IF the rotor and the drive tang are in line.

99% of the time they are not.

Telling people to use the FSM and not telling them that it almost never works is not good.

I’m betting I have 30-40 distributors laying around and not one of them has the rotor lined up with the drive tang.

They'll figure it out. We had to figure it out with NO internet and nothing BUT the service manual and MP manuals and such. We actually had to DIG for it, instead of having it spoon fed.