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Jeep F6-161 specs: 161 ci 6-cylinder, 3.125 x 3.50 in (79.4 x 88.9 mm) bore and stroke, 7.6:1 compression. Rated 90 hp, 1952–1955. Used in the Willys Wagon.
The Jeep F6-161 is undersquare — the 3.5" stroke exceeds the 3.125" 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).
7.6:1 is low by modern standards and generally happy on regular pump fuel.
4 factory variants share these dimensions, rated at 90 hp across 1952–1955.
| Displacement | 161 ci |
|---|---|
| Bore | 3.125" |
| Stroke | 3.5" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 7.6:1 |
| Bore/stroke ratio | 0.893 |
| Fuel type | gas |
|---|---|
| Advertised HP | 90 hp |
| Years | 1952–1955 |
| 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 |
| Static compression | 7.6:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| 1952 | 90 hp | F6-161 |
| 1953 | 90 hp | F6-161 |
| 1954 | 90 hp | F6-161 |
| 1955 | 90 hp | F6-161 |
1 factory vehicle, 1952–1955. Each year opens that model's engine table.