GMC LL8 Specs
GMC LL8 engine specs: 256 ci (4.2L), 6-cylinder, 3.6614" bore x 4.0157" stroke, 10:1 compression.
Dimensions
| Displacement | 256 ci / 4.2 L |
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| Bore | 3.6614" |
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| Stroke | 4.0157" |
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| Cylinders | 6 |
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| Compression ratio | 10:1 |
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| Bore/stroke ratio | 0.912 |
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Construction
| Block material | aluminum |
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| Head material | aluminum |
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| Valvetrain | DOHC |
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| Fuel type | gas |
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| Advertised HP | 275–291 hp |
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What these numbers mean
| Bore/stroke character | 0.912 — undersquare — stroke exceeds bore, which favours low-end torque |
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| Mean piston speed at 6,000 RPM | 4,016 ft/min — in the range typical of performance street engines |
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| Displacement per cylinder | 42.7 ci |
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| Static compression | 10:1 — in the range that usually runs on pump premium |
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Variants sharing these dimensions (2)
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
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| — | 275 hp | LL8 |
| — | 291 hp | LL8 |
Vehicles (6)
- Chevrolet TrailBlazer
- GMC Envoy
- Oldsmobile Bravada
- Buick Rainier
- Saab 9-7X
- Isuzu Ascender
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