[TonyMadrid]

Just got home and checked through a few books. Couldn't find anything that exactly matches what's on your block.

As far as the first part, C9M6015, it does appear that there is a character missing between the M and the 6. The M stands for Mercury and the 6015 is the part #, in this case a block. The character that seems to be missing is the fourth position and would be either an A for Chassis Group, a B for Body Group, or an E for Engine group. In your case it should be an E as th epart is a block.

After that string of characters there may be a Suffix Letter. An A would indicate an original part, a B would be the first revision, a C would be the second revision, and so on.

There may also be a Date Code indicating when the part was cast. This code is usually of the format of 0H14 which would indicate a date of August 14, 1970. Another example would be 5A26 which would indicate January 26, 1975.

As far as what is on yours, FA5, I could not find anything definitive. I could venture a guess that the A5 part may indicate January 5th but the "F" has me baffled, It possibly could be a revision code indicating the 6th revision.

Sorry I couldn't be of more help. Maybe one of the Forum's Gurus can help out.

Tony