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Porsche 923/02 specs: 2.0L (120 ci) 4-cylinder, 94 x 71 mm (3.7008 x 2.7953 in) bore and stroke, 7.6:1 compression. Rated 86 hp, 1976.
The Porsche 923/02 is oversquare — the 3.7008" bore exceeds the 2.7953" stroke by 32.4% — a layout that favors airflow and RPM over leverage at the crank. The 2.7953" stroke does not reach 4,000 ft/min of mean piston speed until about 8,600 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 30.0 ci (492 cc).
7.6:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 3 engines in the Porsche 120ci family, all of them 120 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 120 ci / 2 L |
|---|---|
| Bore | 3.7008" |
| Stroke | 2.7953" |
| Cylinders | 4 |
| Compression ratio | 7.6:1 |
| Bore/stroke ratio | 1.324 |
| Fuel type | gas |
|---|---|
| Advertised HP | 86 hp |
| Years | 1976 |
| Bore/stroke character | 1.324 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,795 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.0 ci |
| Static compression | 7.6:1 — low by modern standards, generally happy on regular pump fuel |
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1 factory vehicle, 1976. Each year opens that model's engine table.