As I recall, that particular Cadillac was basically an extended wheelbase sedan with more rear seat leg room to accomodate a pair of jump seats. More like a factory built basic limo, before stretching cars to extreme dimensions was popular. So, do we want to talk about "regular wheelbase" vehicles or "extended wheelbase" vehicles? I move for the former rather than the latter as the jump seats would take it out of the realm of normal passenger vehicles of that time and put it more into the limosine side of things. Otherwise, we'd have to compare them to the limo conversion Imperials of similar time frames.Just some thoughts,W Bell