Detroit was literally one of the most fortified cities of America during WW2. It was also the most industrialized. GG no re.
The GM motor company starts producing M24 Chaffee tanks at the Cadillac factory in Detroit. These are fast, long range light tanks that use the same gun as the Sherman, but are faster and more maneuverable. While the blueprints remain at TACOM in the Detroit Arsenal Tank Factory in Detroit, various assorted prototypes and complete tanks are scattered around the nations. 3-4 months to reverse engineer and produce.
In addition, Detroit starts to distribute SCR-584 anti-aircraft radar tracking systems, 90mm M1 guns, and 120mm M1 guns to fortifications alongside the Ohio-Michigan border.