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Austin-Healey C-Series 2.6 specs: 161 ci 6-cylinder, 79.4 x 88.9 mm (3.1248 x 3.5000 in) bore and stroke. Built 1957–1959.
The Austin-Healey C-Series 2.6 is undersquare — the 3.5" stroke exceeds the 3.1248" bore by 10.7% — a layout that trades peak RPM for leverage and torque low in the range. 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 6 cylinders displaces 26.8 ci (440 cc).
3 factory variants share these dimensions across 1957–1959.
| Displacement | 161 ci |
|---|---|
| Bore | 3.1248" |
| Stroke | 3.5" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 0.893 |
| Fuel type | gas |
|---|---|
| Years | 1957–1959 |
| Bore/stroke character | 0.893 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,500 ft/min — conservative for a street engine |
| Displacement per cylinder | 26.8 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 |
|---|---|---|
| 1957 | — | C-Series 2.6 |
| 1958 | — | C-Series 2.6 |
| 1959 | — | C-Series 2.6 |
1 factory vehicle, 1957–1959. Each year opens that model's engine table.