Tom Thuerwachter is the Mercury Special Interest Group Leader. Might be a good place to start. Did a search for Bureau and saw some posts but they were all related to OMC products. I know I read a post somewhere about a KD4 Bureau engine.
Kirk
A couple of Wartime Cedarburg factory pictures, looks like Navy motors being manufactures due to color and flywheel size?
Also a couple pictures of a restored Navy motor from Tomahawk not sure of owner? Very Nice Job though.