Note: The famous is the most collected. Serial numbers 501 to 5,000 (1971) are considered early "blue ribbon" tractors. Numbers above 50,000 are 1975-1976 models.

: Modern IH tags (post-1960s) use a "Kind/Code" system. For example, a tag reading 2590009U004452 breaks down into: Kind (259) : The machine type. Code (009) : Specific configuration. Country (U) : "U" for United States. Serial Number (4452)

The actual production number of that machine.

: A separate engine serial number is often stamped directly into the cylinder block, usually above the oil filler tube. Serial Number Reference Tables

Whether you are a collector trying to authenticate a barn find, a farmer looking for the correct parts, or a restorer determining the exact year of your machine, you need one tool above all others: the .