There are 3 sets of numbers used to identify your 1927 AA Stutz. First, there should be a brass tag on screwed onto the firewall which is the serial number of your car. The last 5 digits of it should correspond to a brass plate on the instrument panel. This is the FEDCO number, which was an anti theft idea of the time. The plate on your instrument panel has the Stutz logo with the number immersed behind it - if you look carefully you'll see it. The point of this was if someone stole the car and removed the plate on the firewall, the tag on the instrument panel would still be there to identify which car it was. The FEDCO number used numbers and letters and there is a "code" to it to decipher the letters into numbers. There is also a brass tag on the valve cover of the engine. This is the engine number. This should correspond to the number stamped into the block by the distributor. Sometimes you see titles with the engine number on them for identification. Third, if you remove the passenger side rear bumperette, you'll see a number stamped into the flat end of the frame horn. I believe this number is the "numeric"version of the FEDCO number with no letters.