Reference Details
- Common issue
- A real 427 block, restamped pad, warranty/service engine, or transmission swap may not carry the correct MN/MO suffix and vehicle-matching partial VIN chronology.
- Confidence
- documented
- Correct value
- COPO 9561 L72 engine suffix MN for four-speed cars or MO for TH400 automatic cars, with 1969 drivetrain partial VIN stamping expected on the engine and transmission
- Where to check
- Engine assembly stamp on the big-block pad/alternate 1969 V8 VIN area near the oil filter, plus transmission partial VIN stamping; compare the partial VIN to the vehicle VIN and the suffix to the documented transmission type
