See other engines in this family
Jeep L6-148 specs: 148 ci 6-cylinder, 3.00 x 3.50 in (76.2 x 88.9 mm) bore and stroke. Built 1947–1950. Used in the Willys Wagon. Rod ratio and piston speed.
The Jeep L6-148 is undersquare — the 3.5" stroke exceeds the 3" bore by 14.3% — 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 24.7 ci (404 cc).
It is one of 3 engines in the Jeep 148ci family, all of them 148 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions across 1947–1950.
| Displacement | 148 ci |
|---|---|
| Bore | 3" |
| Stroke | 3.5" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 0.857 |
| Fuel type | gas |
|---|---|
| Years | 1947–1950 |
| Bore/stroke character | 0.857 — 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 | 24.7 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 |
|---|---|---|
| 1947 | — | L6-148 |
| 1948 | — | L6-148 |
| 1949 | — | L6-148 |
| 1950 | — | L6-148 |
1 factory vehicle, 1947–1950. Each year opens that model's engine table.