Well...the rotor is supposed to have the movement you show, that's the advance mechanism. Reach in with some needlenose pliers or whatever, pull the driveshaft up off of the cam gear, just enough to get the two gears clear of each other, then try to rock the shaft side to side to check for any wobble or looseness. Then pull it out and see how the tip of the distributor shaft engages it. Good time to see if the distributor shaft itself wobbles at all within the housing.
Thanks for replying (and watching)!
1. Well, I was trying not to "get into" the advance in the distributor at all (not get into any of the "felt" spring resistance)
by gingerly just using a couple fingers to move the rotor back and forth, but you can see the jobber thingy under
the distributor plate moving as I did it, so I guess I was into the advance a little?
Yeah, my shadetree instinct told me the movement of the rotor was quite normal.
2. Insofar as distributor tip mating with the drive gear goes, you can feel a pretty firm engagement there when you
install the distributor - there's no slop there, it has to be pretty exactly aligned to go in and when it does, it dang
near clicks in. Since the distributor itself has very low miles on it and I make a point of cleaning the hole in the block
where the distributor mounts, it slips right in as long as the tang on the distributor is exactly aligned.
There is no wobble in the distributor, checked that and again, it's fairly new.
3. Good point on checking the drive gear shaft for slop. It always makes me nervous to go after that rascal in an
assembled engine, but I've had it out before (to align it front-back on TDC like it should be) so it shouldn't fight
much. That'll be my next step, in fact.