On piston engines through 1981, the serial number and engine type code are located on a plate mounted at the right front, top of the block, except for the GLC type TC engine, which has the plate on the front of the cylinder head. On 1982-89 models, the engine number is located on a machined pad extending from the cylinder block, just below the No. 1 spark plug (between the distributor and the alternator).
The engine identification number is stamped on the front of the engine between the distributor (or crank angle sensor on later engines) and the alternator.
See Figures 1, 2 and 3