And for Le Mans, the specific classes will be XJ13, Shelby Daytona Coupe and Ferrari 250 GTO.
However, I might do something different and run the final four spots as unclassified, and allow random entries that fit the theme to participate, so cars like the GT40 Mk1 and Mk4, Chapparrall 2D (not the 2J), Alfa Romeo and others would be permitted, but they would only earn 1 point for finishing and bonus points for finishing cleanly.
However, I will be resisting selecting classes that do not allow you to customize the car in some way to identify you from someone else. So there will never be a spec class for the CLK-LM for example, unless there are four guys who REALLY want to run it. For now though, I want to make a point to only race cars that are paintable (or at least can change the number, like Stealth's).