Från http://www.428cobrajet.com/id-block.html Starting in 1967 for the 1968 model year, Ford began stamping partial VIN numbers on some production engine blocks, and this pad is where the numbers would often be stamped on a 428 CJ. The stamping is nearly impossible to see on this particular block, but knowing that those numbers are there gives new meaning to the term "matching numbers" when talking about Ford engines. Videre... I've also received reports from people who have found partial VIN stampings on the rear of the driver's side cylinder head. John