Reference Details
- Common issue
- A replacement 455 with correct-looking accessories but no matching partial VIN/casting context, or a restored car over-corrected to expected head letters without car-specific evidence.
- Confidence
- reported
- Correct value
- 455cid four-barrel engine with casting number 396021 F and a partial VIN stamp formatted as Oldsmobile division, 1968 model year, Lansing plant, and the last six VIN digits; W-46 A/C cars are associated with C-head/casting 394548 and W-45 non-A/C cars with D-head/casting 400370, while the club notes either head has appeared on untouched cars.
- Where to check
- Engine casting surfaces, the small smooth pad on the block below the cylinder head behind the power steering pump, and cylinder-head casting/letter locations.
