This is the serial number. It is simply the sequence number of the V-8 engine built at the Rouge plant in 1936. Nothing can be determined from the number, except that it is in the middle of the range of engine sequence numbers from that year.
Ken's correct. This site (http://www.vanpeltsales.com/FH_web/flathead_serialnumbers.htm) shows the numbers, locations and equally important the font used to stamp them. The number stamped on the frame under the hood should take the format *18-2940186* where the * is a 5 point star. A good DMV will check for the correct number stamped at the factory.