the 3.5 heads are not a good replacement unless you buy the second versions.... do not buy a rebuilt head thay are notorius for having cracks and voids at the #1 & #4 cylinder forcing oil into the coolant jacket. If you are going to use the 3.5 head buy a new one. the rebuilts (which are cleaned up originals) were known to have problems straight from the foundry. When replacing these heads always buy from MB it is worth the redesigned head. By the way the engine # is not on the head. MB puts the head part # there and there is an engine number on the block.