went out of production before the end of 1979. Cadillac's full size car was downsized in 1977 and these smaller bodies just weren't spacious enough for ambulance duty with the advancement of paramedic equipment. Other large GM cars had been used as ambulances as Oldsmobile and Pontiac. I don't think Mopar or Ford made any automobile-based ambulances.
https://youtu.be/XNdoAKSQn-w