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Toyota F specs: 3.9L (236.7 ci) 6-cylinder, 90 x 101.6 mm (3.5433 x 4.0000 in) bore and stroke. Rated 105-125 hp, 1958–1975. Used in the Toyota Land Cruiser.
The Toyota F-series (F) is undersquare — the 4" stroke exceeds the 3.5433" bore by 11.4% — a layout that trades peak RPM for leverage and torque low in the range. The 4" stroke puts mean piston speed at 4,000 ft/min around 6,000 RPM, which is where a production bottom end is generally considered at its limit. Each of the 6 cylinders displaces 39.4 ci (646 cc).
It is one of 11 engines in the F-series family, the smallest at 236.7 ci. 18 factory variants share these dimensions, rated from 105 to 125 hp across 1958–1975.
| Displacement | 236.7 ci / 3.9 L |
|---|---|
| Bore | 3.5433" |
| Stroke | 4" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 0.886 |
| Valvetrain | OHV |
|---|---|
| Fuel type | gas |
| Advertised HP | 105–125 hp |
| Years | 1958–1975 |
| Bore/stroke character | 0.886 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 4,000 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 39.4 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 |
|---|---|---|
| 1958 | 105 hp | F |
| 1959 | 105 hp | F |
| 1960 | 105 hp | F |
| 1961 | 125 hp | F |
| 1962 | 125 hp | F |
| 1963 | 125 hp | F |
| 1964 | 125 hp | F |
| 1965 | 125 hp | F |
| 1966 | 125 hp | F |
| 1967 | 125 hp | F |
| 1968 | 125 hp | F |
| 1969 | — | F |
| 1970 | — | F |
| 1971 | — | F |
| 1972 | — | F |
| 1973 | — | F |
| 1974 | — | F |
| 1975 | — | F |