engine serial numbers
 

Are the Mercruiser engine serial numbers on the valve covers supposed to be the same as the numbers stamped on the front of the block on the deck? Motors are '99 502's and these 2 numbers do not match.
Thanks

no. the numbers on the deck are gm. only merc hp engines actually stamp the block. the regular merc engines have a riveted plate on the rear stbd side of the block above the starter. merc dealers have a list to match gm numbers to merc models

THANKS! I was beginning to wonder if my motors were the originals. That explains why the stamped number has extra letters on the ends does not even come close to the Merc numbering system.

My last boat had a HP465 and the stamped number matched the Merc number. That was my reasoning for asking.