Reference Details
- Common issue
- A 400-cubic-inch casting or GS badge does not by itself verify the GS 400 engine application; the production code and car-specific documentation still need to agree.
- Confidence
- documented
- Correct value
- Team Buick's 1968 engine-number table lists GS 400 engine number PR with 8 cylinders, 400 CID, 340 hp, 10.25 compression, 4BC carburetion, and MAN/AUTO transmission applicability.
- Where to check
- Check the engine production-code stamping; Team Buick's Buick engine-identification page places the 1968-1972 400/430/455 production code between the two front plugs and the exhaust manifold on the left side.