Chevrolet 302ci 12.5:1 Specs
Chevrolet Chevrolet 302ci · 4.000" × 3.000" · 12.5:1 engine specs: 302 ci (4.9L), 8-cylinder, 4" bore x 3" stroke, 12.5:1 compression.
Dimensions
| Displacement | 302 ci / 4.9 L |
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| Bore | 4" |
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| Stroke | 3" |
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| Cylinders | 8 |
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| Configuration | V8 |
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| Compression ratio | 12.5:1 |
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| Rod length | 6.56" |
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| Rod ratio | 2.187 |
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| Bore/stroke ratio | 1.333 |
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| Piston deck clearance | 0.01" |
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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 | 350–360 hp |
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| Years | 2018–2023 |
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What these numbers mean
| Bore/stroke character | 1.333 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
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| Mean piston speed at 6,000 RPM | 3,000 ft/min — conservative for a street engine |
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| Rod ratio | 2.187 — long — less side loading on the cylinder wall, favours high RPM |
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| Displacement per cylinder | 37.8 ci |
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| Static compression | 12.5:1 — high enough that pump premium or better is normally required |
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Cylinder head
| Intake valve diameter | 2.135" |
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| Exhaust valve diameter | 1.595" |
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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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| 2018 | 360 hp | — |
| 2019 | 360 hp | — |
| 2022 | 350 hp | — |
| 2023 | 350 hp | — |
Similar engines
Source: NHRA blueprints — nhra.net blueprints
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