how can you tell if a 1968 road runner is a real hemi?

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Accepted Answer

To tell if a 1968 Plymouth Road Runner is a real factory Hemi, you need to check three main authentication points:

**1. VIN Verification (Most Important)**
- The 5th digit in the VIN must be **"J"** - this is the engine code for the 426 2x4bbl Hemi
- The VIN should start with **"RM"** (Plymouth Road Runner), followed by either:
  - **21** = 2-door sedan/coupe
  - **23** = 2-door hardtop
- Position 6 should be **"8"** for 1968 model year

For example, the VIN **RM21J8A217494** on this vehicle breaks down as:
- R = Plymouth (B-body/Intermediate)
- M = Road Runner (Medium Price Class)
- 21 = 2-door coupe
- **J** = 426 Hemi engine ← This is your authentication key!
- 8 = 1968 model year
- A = Lynch Road, MI assembly plant

**2. Fender Tag Codes**
The fender tag (located on the driver's side inner fender) should show:
- **Code 073** = "426-8bbl Hemi Engine"
- **Code 094** = Hemi automatic transmission
- These codes confirm the car was ordered from the factory with the Hemi package

**3. Engine Stampings**
A factory 426 Hemi block will have:
- Casting numbers: The block should have proper 426 Hemi casting marks
- Some engines may show "**WT**" stamps - these indicate "Water Tested Replacement Block" (factory warranty replacement blocks)
- The engine should have VIN derivative stamps that match the last digits of the car's VIN (when numbers-matching)

**Important Notes for 1968:**
- Only 726 Road Runner Hemis were built in 1968, making these incredibly rare
- Many clones exist with non-factory Hemi swaps
- Even if the original engine is no longer present (like the 1966 date code replacement block in this car), the VIN and fender tag confirm it was factory-built as a Hemi car

Want me to help you find other Hemi Road Runners for comparison? Check out our market page: https://classic.com/m/plymouth/road-runner/1st-gen/hemi/

Lot 7494: 1968 Plymouth Road Runner Hemi

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Lot 7494: 1968 Plymouth Road Runner Hemi

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