Thank you all for your replies. What I am trying to establish is if this engine is an aluminum block 5.0 common to all Mercedes 126 V8 models 1980 to 1991 that start with engine number 117961, 963, ... etc. OR the old 116 model iron block 4.5 liter installed in the 450 series 116 Mercedes cars that would have engine number starting with 116XXXXX?.