Oldsmobile 350ci engine specs: 350 ci (5.7L), 8-cylinder, 4.057" bore x 3.385" stroke, 22.5:1 compression. Plus 1.739 rod ratio.
The Oldsmobile 350ci is oversquare — the 4.057" bore exceeds the 3.385" stroke by 19.9% — a layout that favors airflow and RPM over leverage at the crank. The 3.385" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.739 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.8 ci (717 cc).
At 22.5:1 this is a compression-ignition engine: the ratio is the heat source that lights the fuel, not a knock limit to be managed.
It is one of 3 engines in the Oldsmobile 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 105 hp across 1982–1984.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 4.057" |
| Stroke | 3.385" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 22.5:1 |
| Rod length | 5.885" |
| Rod ratio | 1.739 |
| Bore/stroke ratio | 1.199 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | diesel |
| Advertised HP | 105 hp |
| Years | 1982–1984 |
| Bore/stroke character | 1.199 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,385 ft/min — conservative for a street engine |
| Rod ratio | 1.739 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 43.8 ci |
| Static compression | 22.5:1 — high enough that pump premium or better is normally required |
| Intake valve diameter | 1.875" |
|---|---|
| Exhaust valve diameter | 1.625" |
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 |
|---|---|---|
| 1982 | 105 hp | — |
| 1984 | 105 hp | — |