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Chevrolet 327ci specs: 327 ci (5.4L) 8-cylinder, 4.065 x 3.15 in (103.3 x 80 mm) bore and stroke, 12.5:1 compression. Rated 390 hp, 2020–2023. OHV.
The Chevrolet 327ci is oversquare — the 4.065" bore exceeds the 3.15" stroke by 29.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.15" stroke does not reach 4,000 ft/min of mean piston speed until about 7,600 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 2.083 is long by production standards — less side-load on the cylinder wall and gentler piston acceleration around TDC, the geometry that tolerates high RPM. Each of the 8 cylinders displaces 40.9 ci (670 cc).
12.5:1 on iron heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 20 engines in the Chevrolet 327ci family, all of them 327 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 390 hp across 2020–2023.
| Displacement | 327 ci / 5.4 L |
|---|---|
| Bore | 4.065" |
| Stroke | 3.15" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 12.5:1 |
| Rod length | 6.56" |
| Rod ratio | 2.083 |
| Bore/stroke ratio | 1.29 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 390 hp |
| Years | 2020–2023 |
| Bore/stroke character | 1.290 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,150 ft/min — conservative for a street engine |
| Rod ratio | 2.083 — long — less side loading on the cylinder wall, favours high RPM |
| Displacement per cylinder | 40.9 ci |
| Static compression | 12.5:1 — high enough that pump premium or better is normally required |
| Intake valve diameter | 2.135" |
|---|---|
| Exhaust valve diameter | 1.595" |
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These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2020 | 390 hp | — |
| 2023 | 390 hp | — |