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Oldsmobile 350 specs: 350 ci (5.7L) 8-cylinder, 4.00 x 3.50 in (101.6 x 88.9 mm) bore and stroke, 9:1 compression. Rated 250 hp. Rod ratio and piston speed.
The Oldsmobile Rocket (350) is oversquare — the 4" bore exceeds the 3.5" stroke by 14.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.5" stroke puts mean piston speed at 4,000 ft/min around 6,850 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 43.8 ci (717 cc).
9:1 on iron heads is low by modern standards and generally happy on regular pump fuel.
It is one of 15 engines in the Rocket family, sitting between the 260 ci and 455 ci members. 2 factory variants share these dimensions, rated at 250 hp. Factory fitments include the Oldsmobile Cutlass, Oldsmobile Delta 88, Oldsmobile 442 and 6 others.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 4" |
| Stroke | 3.5" |
| Cylinders | 8 |
| Compression ratio | 9:1 |
| Bore/stroke ratio | 1.143 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 250 hp |
| Bore/stroke character | 1.143 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,500 ft/min — conservative for a street engine |
| Displacement per cylinder | 43.8 ci |
| Static compression | 9:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| — | 250 hp | 350 |
| — | 250 hp | 350 |