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Oldsmobile L74 specs: 330 ci (5.4L) 8-cylinder, 3.938 x 3.385 in (100 x 86 mm) bore and stroke. Rated 320 hp, 1966–1967. Used in the Oldsmobile Cutlass.
The Oldsmobile 330ci (L74) is oversquare — the 3.938" bore exceeds the 3.385" stroke by 16.3% — 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 1.773 is long by production standards — less side-load on the cylinder wall and gentler piston acceleration around TDC, the geometry that tolerates high RPM. Each of the 8 cylinders displaces 41.3 ci (676 cc).
It is one of 6 engines in the Oldsmobile 330ci family, all of them 330 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 320 hp across 1966–1967.
| Displacement | 330 ci / 5.4 L |
|---|---|
| Bore | 3.938" |
| Stroke | 3.385" |
| Cylinders | 8 |
| Configuration | V8 |
| Rod length | 6.002" |
| Rod ratio | 1.773 |
| Bore/stroke ratio | 1.163 |
| Fuel type | gas |
|---|---|
| Advertised HP | 320 hp |
| Years | 1966–1967 |
| Bore/stroke character | 1.163 — 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 | 1.773 — long — less side loading on the cylinder wall, favours high RPM |
| Displacement per cylinder | 41.3 ci |
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 |
|---|---|---|
| 1966 | 320 hp | L74 |
| 1967 | 320 hp | L74 |