K-Code
The engine code designation in the VIN for Mustangs equipped with the 289 cubic inch High Performance (Hi-Po) engine, Ford's factory hot rod motor producing 271 horsepower. The "K" appears in the 5th position of the VIN (example: 5F08K123456) and immediately adds $15,000-$40,000 to the car's value compared to an identical Mustang with a regular 289. Also: the single letter that separates a $45,000 Mustang from an $85,000 Mustang, which is why VIN fraud exists and why you should verify K-code claims with a Marti Report before writing a check.
What 'K-Code' Actually Means
K-code refers specifically to the 289 High Performance engine offered in 1964½-1967 Mustangs.
289 Hi-Po specifications:
- Displacement: 289 cubic inches (4.7L)
- Horsepower: 271 HP @ 6,000 RPM
- Torque: 312 lb-ft @ 3,400 RPM
- Compression ratio: 10.5:1
- Induction: Single 4-barrel carburetor (Autolite 4100)
- Solid lifter camshaft (not hydraulic)
- Screw-in rocker studs
- Special high-performance valve springs
- Stronger connecting rods
- High-flow cylinder heads
Visual identification:
- Chrome open-element air cleaner
- Chrome valve covers (289 High Performance)
- Solid lifter valve train (audible)
- Special exhaust manifolds
- 4-barrel carburetor
Production years:
- 1964½: Rare (limited production)
- 1965: 7,273 units
- 1966: 5,469 units
- 1967: 1,647 units
- Total: ~14,400 units (all years)
Rarity:
K-code represents less than 1% of total Mustang production 1964½-1967. Extremely rare.
I've seen three claimed "K-code" Mustangs. Only one was real—VIN verified, Marti Report confirmed, engine derivative stamp matched. The other two were C-code (regular 289) cars with swapped VIN plates. Fraud is common because K-code is worth so much more.
Why It Matters for Your Mustang
K-code designation dramatically affects value.
Value comparison (1966 fastback example):
- C-code (289 2V): $40,000-$60,000
- A-code (289 4V): $45,000-$65,000
- K-code (289 Hi-Po): $65,000-$110,000
- K-code premium: +$20,000-$50,000
Factors affecting K-code value:
- Numbers-matching K-code engine: +$15,000-$30,000
- Documented history: +$5,000-$15,000
- Concours condition: +$20,000-$40,000
- Rare options (GT, 4-speed): +$10,000-$25,000
Investment potential:
K-code Mustangs appreciate faster than regular Mustangs. Limited production ensures long-term value.
Collectability:
K-code is among most collectible production Mustangs (below Shelby and Boss, above regular models).
Cost Impact
| Repair Type | Typical Cost (LA) | Labor Hours |
|---|---|---|
| K-code rebuild (standard) | $10,000-$21,000 | Regular 289 $5,000-$10,000 + $5,000-$11,000 premium |
| K-code rebuild (concours) | $15,000-$30,000 | Date-coded parts add $2,000-$6,000 premium |
| K-code car purchase (project) | $45,000-$60,000 | C-code project $25,000-$40,000 + $20,000-$20,000 premium |
| K-code car (restored) | $65,000-$110,000 | C-code restored $40,000-$60,000 + $25,000-$50,000 premium |
*K-code adds $20,000-$50,000 to Mustang value. Verify authenticity with VIN check and Marti Report before buying - fraud is common.
Ask me how I know these numbers.
Common Issues
VIN Fraud
VIN plate swapping - steal K-code VIN, install on C-code car, sell at $40,000 markup
Engine Swapping
K-code engine in C-code car - not original, not as valuable, verify VIN derivative stamp
Re-Stamping
Grind off C-code engine stamp, re-stamp with K-code - impossible to detect without expert inspection
Maintenance Requirements
Solid lifter cam requires valve adjustment every 3,000-5,000 miles - not maintenance-free
Verification Cost
Marti Report $40-$50 + expert inspection $200-$500 = $250-$550 to verify authenticity
See This in Action
- K-Code Mustang Buyer's Guide
Authentication tips, value analysis, and fraud prevention strategies
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.