I have been hunting down some parts to try to assemble a correct unitized distributor for the car. I recently got one 1973 1112203 off of ebay, a 1974 1112810 from a trade for an old holley carb I wasn't using, and got a rebuilt 1973 1112203 from an auto parts store. I do still need an actual 1972 1112133 in case anyone has a useable core out there.
These contraptions were a standard option on the 455HO Formula and optional on the Trans Am. They were somewhat notorious for glitches, being the first self-contained transistorized ignition developed by Pontiac. In evolutionary terms, if the the later HEI distributor was a modern human, then the Unitized Distributor was a Neanderthal.
The big problem was that the parts were unique and never produced by the aftermarket. The distributor cap, the rotor, the coil, and most of all, the wire set were unique and insanely expensive even back in 1972. The ignition module was housed in the base with wires that connected to the coil pack. The wire set was a molded one piece octopus that required complete replacement as a unit if you burned or broke a single wire. It sold new from the dealer, for several hundred dollars back when a regular points ignition wire set was around $20. So when something happened, the entire distributor was usually tossed and a newer HEI was installed in its place for 1/4 the price.
Here's one assembled:
Here's the three I have now
