Date Codes
Stamped or cast codes on parts indicating when they were manufactured—month, year, sometimes week or day. Used by Ford and suppliers to track production, now used by concours judges to verify parts were manufactured close to the car's build date. Also: the reason a perfectly good carburetor from 8 months after your car was built will cost you points, because concours judging is a harsh mistress.
What 'Date Codes' Actually Means
Date codes are manufacturer markings showing when a part was made.
Common date code formats:
Casting date codes (engine, transmission):
- Letter = Month (A=Jan, B=Feb, etc.)
- Number = Day
- Number = Year
- Example: "C15-7" = March 15, 1967
Stamped codes (accessories):
- Various formats by manufacturer
- Autolite: Month-Day-Year
- Motorcraft: Week-Year
- Example: "7C15" = March 15, 1967
Glass date codes:
- Numbers in corner
- Complex format
- Month and year
- Example: "67 3" = March 1967
Hose and belt codes:
- Printed on part
- Quarter and year
- Example: "1Q67" = First quarter 1967
Why date codes exist:
Quality control, warranty tracking, recall identification. Ford didn't intend them for concours judging 50 years later.
I once bought a "numbers-matching" engine. Block was correct. Heads were dated 18 months AFTER the car was built. Not matching, not original. Date codes revealed the truth. Saved me from a $15,000 mistake.
Why It Matters for Your Mustang
Date codes matter ONLY for concours judging and authentication.
Concours restoration:
- Parts dated within months of build date
- Judges verify date codes
- Wrong dates = points deduction
- Major components critical (engine, transmission)
- Accessories important (carburetor, distributor, alternator)
Show quality restoration:
- Date codes not critical
- Correct parts matter, dates don't
- Judges don't check (usually)
- Use best available parts regardless of date
Driver quality:
- Date codes irrelevant
- Function and reliability matter
- Modern parts often better anyway
Authentication:
- Date codes verify originality
- Help identify numbers-matching components
- Protect against fraud
- Increase value (if correct)
The reality:
99% of Mustang owners don't need to worry about date codes. 1% building concours cars obsess over them.
Cost Impact
| Repair Type | Typical Cost (LA) | Labor Hours |
|---|---|---|
| Generic correct part | $100 | Standard pricing |
| Date-coded correct part | $300-$1,000 | Premium 3-10x for correct date codes |
| Complete date-coded build premium | +$10,000-$50,000 | 50-100 parts × $200-$500 premium each |
*Date codes only matter for concours builds. Finding parts dated to specific build month can take years and adds $10,000-$50,000 to restoration cost.
Ask me how I know these numbers.
Common Issues
Hunting Takes Time
Finding parts dated to specific build month can take YEARS - serious concours builders start collecting early
Premium Pricing
Date-coded parts cost 3-10x generic correct parts - $300-$1,000 vs $100
Reproductions Have Wrong Dates
Most reproductions have modern dates or no dates - immediate concours disqualification
Acceptable Windows
Engine 1-6 months before build, accessories 1-3 months - strict enforcement at national concours
Only Matters for Concours
99% of owners don't need to worry - date codes irrelevant for show quality or driver builds
See This in Action
- Concours Restoration Guide
Complete date code requirements and acceptable windows for different components
Want to Learn More?
Download the Mustang Restoration Starter Kit (LA Edition) for:
- Complete terminology reference guide
- Cost estimation worksheets
- Pre-purchase inspection checklist
- Shop interview questions
- Project timeline planning tools
No upsells. No bait-and-switch. Just the information Dorian wishes he'd had before he bought his first project car.