Sharon,
I'm afraid I don't have an answer to your question, but congratulations on a well deserved trophy!
I do know that the class includes limousines, such as yours, that have been stretched/modified by the various coachbuilders. It also includes the standard factory Cadillac Series 75 limousines and formal sedans. I'm not sure if it includes anything else.
The answer to your question can probably be found in official PCS publication PCS-5 : Standard Car Classes. This publication is referenced in the Judging Manual (PCS-12), but unfortunately, I don't have a copy to quote from.
Not much help I'm afraid. Perhaps someone here has a copy of PCS-5 they can quote.
Nick
