Date Codes
Short answer: A few weeks’ gap between an engine’s date code and the Fisher Body trim-tag date is completely normal — nothing to worry about. The rule of thumb for drivetrain parts is roughly 2 weeks to 3 months before the body build date (about 6 weeks is the usual maximum), and generally not after, though exceptions exist.
- The trim-tag date is when the body shell was assembled at Fisher Body — not final assembly. The final date is the “Invoice Date” on the Billing History (when the car was certified to ship).
- Worked example: a body shell scheduled the 4th week of October 1967 (the 23rd–27th), with a “WK” block (date code I177) cast Oct. 17, 1967 — cast on a Tuesday, likely assembled around the 20th–23rd, then a couple more days to reach Lordstown for final assembly. So it could easily have gone into a body built that same week.
- Low-production cars were often built in batches, so many of the same model/color/engine ran through within the same period.
As always with date codes, there are no absolutes — inventory control 30 years ago wasn’t what it is today.
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Content last modified: June 13, 2026 at 10:06 am
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