Pontiac 400ci 8.351:1 Specs
Pontiac Pontiac 400ci · 4.125" × 3.750" · 8.351:1 engine specs: 400 ci (6.6L), 8-cylinder, 4.125" bore x 3.75" stroke, 8.351:1 compression.
Dimensions
| Displacement | 400 ci / 6.6 L |
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| Bore | 4.125" |
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| Stroke | 3.75" |
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| Cylinders | 8 |
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| Configuration | V8 |
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| Compression ratio | 8.351:1 |
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| Rod length | 6.625" |
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| Rod ratio | 1.767 |
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| Bore/stroke ratio | 1.1 |
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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 | 170–185 hp |
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| Years | 1975–1976 |
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What these numbers mean
| Bore/stroke character | 1.100 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,750 ft/min — in the range typical of performance street engines |
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| Rod ratio | 1.767 — long — less side loading on the cylinder wall, favours high RPM |
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| Displacement per cylinder | 50.0 ci |
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| Static compression | 8.351:1 — low by modern standards, generally happy on regular pump fuel |
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Cylinder head
| Intake valve diameter | 2.113" |
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| Exhaust valve diameter | 1.663" |
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Variants sharing these dimensions (4)
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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| 1975 | 170 hp | — |
| 1975 | 185 hp | — |
| 1976 | 170 hp | — |
| 1976 | 185 hp | — |
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