I have been late to this party, so to speak. I'm the current director of the Personalized Chevy Chapter and I just read all the comments in this thread. Every VCCA class (stock, HPOCF, CDPC & PCC) has their own rules. I appreciate that it can be frustrating to find out that your Chevy does not "fit in" with any of these classes. There are reasons for these rules. As far as the PCC is concerned, we had to provide some "separation" between our class and the stock & CDPC classes. We did not want a vehicle to win an award in class judging, for example, and then qualify for a PCC award. Same for CDPC. That is why we require 3 significant "visual" mods to qualify for the contemporary class. This would prevent qualification in class judging at the same time. Also, we do not count "reliability" mods like CDPC accepts. If your vehicle qualifies for a class judging award or CDPC certification, it is unlikely it will qualify for PCC judging. This is by design. However, a well restored vehicle with at least a few major visible mods would do well in PCC judging. Mods can't be from the same model/year (or they would not be recognizable as a mod without a VIN analysis).
Our website (pccvcca.org) has all kinds of information including a slideshow of past winners so that a prospective PCC member could see what might be expected for judging. Our judging form lists "countable" mods for the exterior, interior, engine bay & chassis. This was intended to help the member understand what we are looking for. It's a good idea to read over these acceptable mods before asking questions. The number of mods determines the class but only the condition determines the award (junior/senior).
The sleeper class is a new addition this year. It is for stock-looking vehicles with replacement engines (e.g., small block V8 in a pre-1955 or a big block in a pre-1958) or a documented "built" engine. We already have a few candidates.