Buying checks

Casting Date vs Serial Number

Every vintage tractor carries two kinds of dates, and confusing them costs buyers money. The serial number identifies the tractor (or, on a Ford, its engine) and was applied at the end of production. A casting date code is molded into individual parts and records the day that lump of iron was poured. They are supposed to disagree — by a little. When they disagree by a lot, something on the tractor is not original.

Why casting dates always run older

Fresh castings are brittle. Ford's own process held them at least 30 days before machining, then the machined block waited again for assembly, and the serial was stamped only after the assembled engine passed inspection. So on an honest tractor: casting dates first (weeks to months ahead), serial last. A casting dated a few months before the serial's model year is the normal signature of an original tractor.

How the codes read

Ford: month letter (A = January … L = December), day, then the year's last digit — F262 reads June 26 of a year ending in 9. International Harvester: month and day as numbers separated by screw-head marks, then a year letter that cycles I = 1939, J = 1940 … through Z = 1956 (full table in our IH casting date guide). UK Massey Ferguson 35: month letter, day, and a year letter F = 1957 to M = 1964.

The check, step by step

Decode the serial and note the model year.
Read casting codes on the biggest castings: engine block, transmission case, rear axle housings.
Original pattern: all codes fall in the serial's year or the few months before it, and they cluster together.
Swap pattern: one casting — usually the block — is years newer or older than the rest. That part was replaced, and on a Ford a replaced block often carries the serial with it, which is how tractors get misdated.
No pattern at all (codes scattered across a decade): the tractor is a parts assembly. Price it as one.

The full worksheet version of this check — where to find each code, family by family, with recording boxes — is one of the core pieces of the Buyer's Check Kit below.

The $39 Buyer's Check Kit

The decoder gives you the year. The kit gives you the rest of the check before money changes hands: serial-verification worksheets, the two-numbers check that catches swapped engines, year-split parts traps, and an inspection checklist for each family.

Included in the $39 Buyer's Check Kit

See what's inside