[sonjaab]

76.........As far as the Clark St. Cadillac plant. I think it was the only plant producing Caddies untill 12/18/87.
The last Cadillac produced there was the 7,782,466 one.

All Devilles, Fleetwoods and Eldos were produced there at that time.
Heres a pic and some info:
One of the great achievements in Cadillac's long, successful history was the completion in 1921 of what Cadillac considered to be the finest automobile works in the world. Until then the Cadillac was built in 77 different buildings scattered about Detroit. The new plant at Clark Avenue comprised 13 buildings on 47 acres providing more than 56 acres of work space, that is more than 2,464,000 square feet. In the early Nineties Cadillac gave up the latter premises, moving to more modern ones in Warren, in N. Detroit.
(note that this sez untill the early 90s while other info sez 12/18/87....Hmmmm)

EDIT: Yup its wrong....Closed in 87
In addition to production vehicles, the Cadillac Historical Collection includes concept cars, landmark engines such as the first mass-produced V8 engine, and memorabilia from the Clark Street facility in Detroit, where all Cadillacs were built from 1921 to 1987.
AND:
In 1921, the Clark Street Cadillac factory begins production. At the time, it is the most modern plant in the industry. It remains in production until 1987.