The distributor is not supposed to be turned, and that's the reason for the black plastic insert into the slot - the slot being just a casting design remnant from the days when the distributor was the source of the timing. Now that, in your car, the timing source is from the crankshaft, the distributor clocking is only important from the standpoint of delivering the spark to the correct plug over the range of timing adjustment provided by the ignition controller. The wide contact assures that range can be accommodated.

The suggestion to check the harmonic balancer had shifted is probably based on your description of the timing you see. Myself, I doubt it is off just a few degrees, but rather you are seeing the correct timing which is of course retarded by the ICU which defaults retarded when it senses a problem with the KS or an out-of-range condition. Still, if the ICU is OK, and you reset its adapting memory by momentarily removing power (fuse 6 or the pal fuse if you've a late version 93), running cold you should see it attempt to advance again until it repeats the limp-home retarded default. Still doesn't hurt to check your pulley. Easiest way is rather simple -- just pull spark plug #1 and stick a popsicle stick in there and see that you get tdc when it is tdc. Very accurate - easily within one tb tooth.

Did I miss somewhere you answered the several questions about the history of the car and its pinging problem?
--
Art Benstein near Baltimore

Expert: An "ex" is a has-been and a "spurt" is a little drip under pressure.