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Porsche 901/10 specs: 2.0L (121.5 ci) 6-cylinder, 80 x 66 mm (3.1496 x 2.5984 in) bore and stroke, 9.9:1 compression. Rated 170 hp, 1969.
The Porsche 901/10 is oversquare — the 3.1496" bore exceeds the 2.5984" stroke by 21.2% — a layout that favors airflow and RPM over leverage at the crank. The 2.5984" stroke does not reach 4,000 ft/min of mean piston speed until about 9,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 20.3 ci (332 cc).
9.9:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.
It is one of 9 engines in the 901 family, all of them 121.5 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 121.5 ci / 2 L |
|---|---|
| Bore | 3.1496" |
| Stroke | 2.5984" |
| Cylinders | 6 |
| Compression ratio | 9.9:1 |
| Bore/stroke ratio | 1.212 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 170 hp |
| Years | 1969 |
| Bore/stroke character | 1.212 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,598 ft/min — conservative for a street engine |
| Displacement per cylinder | 20.3 ci |
| Static compression | 9.9:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
1 factory vehicle, 1969. Each year opens that model's engine table.