Including the $336 million investment it announced on Dec. 7 for production of the Chevrolet Volt at the Detroit-Hamtramck plant, General Motors Co. will spend more than $700 million in several Michigan factories to bring the plug-in hybrid (GM prefers to call it an electric car with extended-range capabilities) to market in late 2010. The other investments involve eight Michigan plants, including ones in Grand Blanc (tooling), Brownstown Township (battery pack), Bay City (camshafts and connecting rods), and Flint (1.4-L engine-generator). To minimize costs and optimize flexibility in the Hamtramck body shop, GM will re-use some equipment from other GM facilities. Prototype production is slated to begin in the spring, with regular production commencing later in the year. About 1200 workers currently are employed at Hamtramck, where the Cadillac DTS and Buick Lucerne are built.