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Chevrolet 348ci specs: 348 ci (5.7L) 8-cylinder, 4.125 x 3.25 in (104.8 x 82.6 mm) bore and stroke, 9.5:1 compression. Rated 250-280 hp, 1958–1961.
The Chevrolet 348ci is oversquare — the 4.125" bore exceeds the 3.25" stroke by 26.9% — a layout that favors airflow and RPM over leverage at the crank. The 3.25" stroke does not reach 4,000 ft/min of mean piston speed until about 7,400 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 43.5 ci (713 cc).
9.5:1 on iron heads is in the range that usually runs on pump premium; iron holds heat, so treat it as the less forgiving side of that range.
It is one of 13 engines in the Chevrolet 348ci family, all of them 348 ci — the differences between them are in compression, heads and rating, not displacement. 8 factory variants share these dimensions, rated from 250 to 280 hp across 1958–1961.
| Displacement | 348 ci / 5.7 L |
|---|---|
| Bore | 4.125" |
| Stroke | 3.25" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 9.5:1 |
| Bore/stroke ratio | 1.269 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Valves per cylinder | 2 |
| Induction | 4-bbl |
| Advertised HP | 250–280 hp |
| Years | 1958–1961 |
| Bore/stroke character | 1.269 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,250 ft/min — conservative for a street engine |
| Displacement per cylinder | 43.5 ci |
| Static compression | 9.5:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1958 | 250 hp | Turbo-Thrust |
| 1958 | 280 hp | Super Turbo-Thrust |
| 1959 | 250 hp | Turbo-Thrust, RPO 576 |
| 1959 | 280 hp | Super Turbo-Thrust, RPO 573 |
| 1960 | 250 hp | Turbo-Thrust, RPO 576 |
| 1960 | 280 hp | Super Turbo-Thrust, RPO 573 |
| 1961 | 250 hp | Turbo-Thrust, RPO 576 |
| 1961 | 280 hp | Super Turbo-Thrust, RPO 573 |