If it is a 1946 model it could well be a truck built to War Production Board specs for an essential industry. JFFL has a GMC which I believe to be from the same era. I posted what I know about the subject on his GMC. If your Chev is a truck that was built to WPB specs, it could well have been a specialized truck for an essential industry.. Possibly a pumper. The vehicles built to WPB specs do not appear in civilian parts books.