Date Codes

Q: Date Codes

While comparing the date code on my 1967 engine to the Fisher Body Tag, the dates are about three weeks apart. Should I be concerned my engine is not original even though it has the correct engine code (matches docs)?

A: As for date coding, the general rule of thumb for drivetrain components compared to Body Assy Date is anywhere from 2 weeks to 3 months. I’ve seen documented cases where some components were the week before Body Build and as distant as 3 months for things like an alternator. Generally, 6 weeks is the usual maximum. Keep in mind that there are no absolutes when it comes to date coding. Inventory Control 30 years ago was not like it is today. Most people will say that NEVER should a drivetrain component be dated AFTER the Body Build Date however, “never say never”. There have been special cases where the entire engine assy had a casting date after the Body Build Date. This could have been the result of production shortages and/or special build orders.

Also, remember that the Fisher Body Build Date on the firewall Trim Tag is not the final assy date. This Month & Week Code denotes the week that the body shell was assembled at Fisher Body. Again, in special cases, the body shell might have been pulled or put aside from the regular production flow due to a special order or part shortages. The Final Assy Date can be found on the Billing History. Listed as the “Invoice Date”, this is when the car left the final assembly line and was ‘certified’ to be shipped (bought-off). Once again, there could have been factors that delayed this date from being assigned to the vehicle or shipped. Part shortages, mis-builds, repairs would delay buy-off.

Your Firebird body shell was scheduled and assembled during the 4th week of October 1967 (23rd – 27th). This was the basic painted shell with glass, carpet, headliner, seats, some trim. From there,. it was transferred to the Final Assy Plant (Lordstown, OH) for Final Assy. This is where the front fenders, hood, bumpers, trim and drivetrain were installed. The Invoice Date on your Billing History would tell you when the car left Final Assy. The “WK” Engine Block you have (I177) was cast on Oct. 17th 1967. From there it was sent to the Engine Assy Plant and then to the vehicle Final Assy Plant where additional components were added to it before being installed to the vehicle. One could estimate that if it was cast on the 17th (Tues.) then it was probably not assembled until the 20th or 23rd. Figure another couple of days until it arrived at Lordstown for Final Assy into the car. In this hypothetical scenario, there is a chance that this particular engine COULD have been installed into a Body built during the 4th week of Oct. 1967. Variables would be how long it sat at the foundry, shipping time, scheduling and routing through selectivity banks, etc.

Often times, lower production vehicles were built according to a batch order. This would result in many of that particular model, color, engine being routed through production within the same week or period of time. This explains the Body Unit Number found on the Trim Tag and special in-plant codes found on the corner of the Trim Tag (usually found on Van Nuys or Norwood cars in late 1968 or 1969).

Hope this helped. As always, this information is from various sources and research others or myself have done. Exceptions usually DO exist to every rule.

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