Oldsmobile 225ci 9:1 Specs
Oldsmobile Oldsmobile 225ci · 3.75" × 3.4" · 9:1 engine specs: 225 ci (3.7L), 6-cylinder, 3.75" bore x 3.4" stroke, 9:1 compression.
Dimensions
| Displacement | 225 ci / 3.7 L |
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| Bore | 3.75" |
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| Stroke | 3.4" |
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| Cylinders | 6 |
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| Compression ratio | 9:1 |
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| Rod length | 5.965" |
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| Rod ratio | 1.754 |
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| Bore/stroke ratio | 1.103 |
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Construction
| Induction | 1-1 |
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| Advertised HP | 155 hp |
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| Years | 1964–1965 |
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What these numbers mean
| Bore/stroke character | 1.103 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,400 ft/min — conservative for a street engine |
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| Rod ratio | 1.754 — long — less side loading on the cylinder wall, favours high RPM |
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| Displacement per cylinder | 37.5 ci |
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| Static compression | 9:1 — low by modern standards, generally happy on regular pump fuel |
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Cylinder head
| Chamber volume | 54.08 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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| 1964 | 155 hp | — |
| 1965 | 155 hp | — |
Similar engines
Source: NHRA blueprints — nhra.net blueprints
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