American Motors 390ci 10:1 Specs
American Motors American Motors 390ci · 4.165" × 3.574" · 10:1 engine specs: 390 ci (6.4L), 8-cylinder, 4.165" bore x 3.574" stroke, 10:1 compression.
Dimensions
| Displacement | 390 ci / 6.4 L |
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| Bore | 4.165" |
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| Stroke | 3.574" |
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| Cylinders | 8 |
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| Compression ratio | 10:1 |
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| Rod length | 5.858" |
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| Rod ratio | 1.639 |
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| Bore/stroke ratio | 1.165 |
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Construction
| Induction | 1-4 |
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| Advertised HP | 325–340 hp |
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| Years | 1970 |
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What these numbers mean
| Bore/stroke character | 1.165 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,574 ft/min — in the range typical of performance street engines |
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| Rod ratio | 1.639 — moderate — the range most production V8s fall in |
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| Displacement per cylinder | 48.8 ci |
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| Static compression | 10:1 — in the range that usually runs on pump premium |
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Cylinder head
| Chamber volume | 49.1 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 (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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| 1970 | 325 hp | — |
| 1970 | 340 hp | — |
Similar engines
Source: NHRA blueprints — nhra.net blueprints
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