I'm not an armor builder, but this website popped up while searching for Pratt and Whitney R-2800 C-series aircraft engines, as Chevrolet built both R-2800 and R-1830 engines in WW2. I thought the photos of the various Chevrolet-built armored and softskinned vehicles might be of interest to many of you- some neat modeling projects here. Enjoy!
Mike
http://usautoindustryworldwartwo.com/General Motors/chevrolet.htm