Buick 401ci 10.25:1 Specs
Buick Buick 401ci · 4.188" × 3.64" · 10.25:1 engine specs: 401 ci (6.6L), 8-cylinder, 4.188" bore x 3.64" stroke, 10.25:1 compression.
Dimensions
| Displacement | 401 ci / 6.6 L |
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| Bore | 4.188" |
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| Stroke | 3.64" |
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| Cylinders | 8 |
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| Compression ratio | 10.25:1 |
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| Rod length | 6.22" |
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| Rod ratio | 1.709 |
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| Bore/stroke ratio | 1.151 |
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| Piston deck clearance | 0.028" |
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Construction
| Induction | 1-2 |
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| Advertised HP | 280–325 hp |
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| Years | 1963–1966 |
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What these numbers mean
| Bore/stroke character | 1.151 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,640 ft/min — in the range typical of performance street engines |
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| Rod ratio | 1.709 — moderate — the range most production V8s fall in |
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| Displacement per cylinder | 50.1 ci |
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| Static compression | 10.25:1 — in the range that usually runs on pump premium |
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Cylinder head
| Intake valve diameter | 1.875" |
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| Exhaust valve diameter | 1.5" |
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| Chamber volume | 123.72 cc |
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| Rocker ratio | 1.6:1 |
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| Lifter type | hydraulic |
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Variants sharing these dimensions (5)
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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| 1963 | 280 hp | — |
| 1963 | 325 hp | — |
| 1964 | 325 hp | — |
| 1965 | 325 hp | — |
| 1966 | 325 hp | — |
Similar engines
Source: NHRA blueprints — nhra.net blueprints
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