Fiat was very thoughtful in their engine numbering system; the first six digits of the number on the engine's tag tell you all you need to know about the engine. The chart below will illustrate how to decipher the code:

In the above instance, we have a dry sleeve, 3 cylinder, agricultural, naturally aspirated(non-Turbo), 104x110mm engine. The blank line after the number on the chart is reserved for the engine's serial number.