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Ford 300 Six specs: 300 ci (4.9L) 6-cylinder, 4.00 x 3.98 in (101.6 x 101.1 mm) bore and stroke. Rated 115-120 hp, 1973–1986. Used in the Ford F-250. OHV.
The Ford 300 Six is close to square: 4" bore against 3.98" stroke, within 0.5%, which splits the difference between a high-revving layout and a torque layout. The 3.98" stroke puts mean piston speed at 4,000 ft/min around 6,050 RPM, which is where a production bottom end is generally considered at its limit. Each of the 6 cylinders displaces 50.0 ci (819 cc).
It is one of 7 engines in the 240/300 Big Six family, the largest at 300 ci. 27 factory variants share these dimensions, rated from 115 to 120 hp across 1973–1986.
| Displacement | 300 ci / 4.9 L |
|---|---|
| Bore | 4" |
| Stroke | 3.98" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 1.005 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 115–120 hp |
| Years | 1973–1986 |
| Bore/stroke character | 1.005 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,980 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 50.0 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 |
|---|---|---|
| 1973 | — | 300 Six |
| 1974 | — | 300 Six |
| 1974 | 118 hp | 300 Six |
| 1975 | — | 300 Six |
| 1975 | 120 hp | 300 Six |
| 1976 | — | 300 Six |
| 1976 | 120 hp | 300 Six |
| 1977 | — | 300 Six |
| 1977 | 120 hp | 300 Six |
| 1978 | — | 300 Six |
| 1978 | 120 hp | 300 Six |
| 1979 | — | 300 Six |
| 1979 | 117 hp | 300 Six |
| 1980 | — | 300 Six |
| 1980 | 117 hp | 300 Six |
| 1981 | — | 300 Six |
| 1981 | 115 hp | 300 Six |
| 1982 | — | 300 Six |
| 1982 | 115 hp | 300 Six |
| 1983 | — | 300 Six |
| 1983 | 115 hp | 300 Six |
| 1984 | — | 300 Six |
| 1984 | 115 hp | 300 Six |
| 1985 | — | 300 Six |
| 1985 | 120 hp | 300 Six |
| 1986 | — | 300 Six |
| 1986 | 115 hp | 300 Six |