Pontiac 250ci 9:1 Specs
Pontiac Pontiac 250ci · 3.877" × 3.535" · 9:1 engine specs: 250 ci (4.1L), 6-cylinder, 3.877" bore x 3.535" stroke, 9:1 compression.
Dimensions
| Displacement | 250 ci / 4.1 L |
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| Bore | 3.877" |
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| Stroke | 3.535" |
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| Cylinders | 6 |
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| Compression ratio | 9:1 |
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| Rod length | 5.7" |
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| Rod ratio | 1.612 |
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| Bore/stroke ratio | 1.097 |
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| Piston deck clearance | 0.014" |
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Construction
| Induction | 1-1 |
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| Advertised HP | 175 hp |
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| Years | 1968–1969 |
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What these numbers mean
| Bore/stroke character | 1.097 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,535 ft/min — in the range typical of performance street engines |
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| Rod ratio | 1.612 — moderate — the range most production V8s fall in |
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| Displacement per cylinder | 41.7 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
| Intake valve diameter | 1.923" |
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| Exhaust valve diameter | 1.603" |
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| Chamber volume | 65 cc |
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| Rocker ratio | 1.5:1 |
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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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| 1968 | 175 hp | — |
| 1969 | 175 hp | — |
Similar engines
Source: NHRA blueprints — nhra.net blueprints
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