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Buick 350ci specs: 350 ci (5.7L) 8-cylinder, 4.001 x 3.484 in (101.6 x 88.5 mm) bore and stroke, 10.1:1 compression. Rated 260 hp, 1994–1997. OHV.
The Buick 350ci is oversquare — the 4.001" bore exceeds the 3.484" stroke by 14.8% — a layout that favors airflow and RPM over leverage at the crank. The 3.484" stroke puts mean piston speed at 4,000 ft/min around 6,900 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.636 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.8 ci (717 cc).
10.1:1 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 4 engines in the Buick 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions, rated at 260 hp across 1994–1997.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 4.001" |
| Stroke | 3.484" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10.1:1 |
| Rod length | 5.7" |
| Rod ratio | 1.636 |
| Bore/stroke ratio | 1.148 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 260 hp |
| Years | 1994–1997 |
| Bore/stroke character | 1.148 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,484 ft/min — conservative for a street engine |
| Rod ratio | 1.636 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 43.8 ci |
| Static compression | 10.1:1 — 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 |
|---|---|---|
| 1994 | 260 hp | — |
| 1995 | 260 hp | — |
| 1996 | 260 hp | — |
| 1997 | 260 hp | — |