The number stamped on the small block on the front of the block just below the driver's side head is the information from the engine assembly plant that built the engine...
The VIN number of the car that it was built with is on the flat spot on the passenger side of the block just above the oil pan and the factory stamps that on when they install it in the car/truck... The VIN numbers on the blocks can be whole or just the last 8 digits of the VIN depending on what year the engine is...
A warranty/replacement/service engine will have the engine assembly plant information stamped on the front of the block below the left head, but no number on the flat pad above the oil pan on the passenger side because it wasn't installed in a factory.....
