As an example, a 2013 engine would read something like this, 1013426. The date code for the engine is built into the serial number after the first two numbers. However, the most accurate way is to look at the serial number on the block, which is located on the drivers side, rear, on the extended part of the deck surface that goes over the bell housing area. For instance a 2009 engine would say 9PO4, a 2006 engine would say 6P04, etc. These numbers are located on the Passenger side front, on a square pad on the deck surface. The first way is to look at the numbers on the front of the block. There are two ways to determine the year your 604 was manufactured.
