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Chevrolet 346ci specs: 346 ci (5.7L) 8-cylinder, 3.898 x 3.622 in (99 x 92 mm) bore and stroke, 10.2:1 compression. Rated 305-350 hp, 1998–2004.
The Chevrolet 346ci is oversquare — the 3.898" bore exceeds the 3.622" stroke by 7.6% — a layout that favors airflow and RPM over leverage at the crank. The 3.622" stroke puts mean piston speed at 4,000 ft/min around 6,650 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.684 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.3 ci (709 cc).
10.2:1 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 2 engines in the Chevrolet 346ci family, all of them 346 ci — the differences between them are in compression, heads and rating, not displacement. 12 factory variants share these dimensions, rated from 305 to 350 hp across 1998–2004.
| Displacement | 346 ci / 5.7 L |
|---|---|
| Bore | 3.898" |
| Stroke | 3.622" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10.2:1 |
| Rod length | 6.1" |
| Rod ratio | 1.684 |
| Bore/stroke ratio | 1.076 |
| Piston deck clearance | 0.052" |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 305–350 hp |
| Years | 1998–2004 |
| Bore/stroke character | 1.076 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,622 ft/min — in the range typical of performance street engines |
| Rod ratio | 1.684 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 43.3 ci |
| Static compression | 10.2:1 — 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 |
|---|---|---|
| 1998 | 305 hp | — |
| 1998 | 320 hp | — |
| 1999 | 305 hp | — |
| 1999 | 320 hp | — |
| 2000 | 305 hp | — |
| 2000 | 345 hp | — |
| 2001 | 310 hp | — |
| 2001 | 345 hp | — |
| 2002 | 310 hp | — |
| 2002 | 345 hp | — |
| 2003 | 350 hp | — |
| 2004 | 350 hp | — |