GMC 347 Specs
GMC 347 engine specs: 347 ci (5.7L), 8-cylinder, 4" bore x 3.5" stroke, 10:1 compression.
Dimensions
| Displacement | 347 ci / 5.7 L |
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| Bore | 4" |
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| Stroke | 3.5" |
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| Cylinders | 8 |
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| Compression ratio | 10:1 |
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| Bore/stroke ratio | 1.143 |
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Construction
| Block material | cast iron |
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| Head material | cast iron |
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| Valvetrain | OHV |
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| Fuel type | gas |
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| Advertised HP | 270 hp |
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What these numbers mean
| Bore/stroke character | 1.143 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,500 ft/min — conservative for a street engine |
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| Displacement per cylinder | 43.4 ci |
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| Static compression | 10:1 — in the range that usually runs on pump premium |
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Vehicles (3)
- Pontiac Chieftain
- Pontiac Star Chief
- Pontiac Bonneville
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