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Ford 289ci specs: 289 ci (4.7L) 8-cylinder, 4.00 x 2.87 in (101.6 x 72.9 mm) bore and stroke, 11.6:1 compression. Rated 271 hp, 1965.
The Ford 289ci is oversquare — the 4" bore exceeds the 2.87" stroke by 39.4% — a layout that favors airflow and RPM over leverage at the crank. The 2.87" stroke does not reach 4,000 ft/min of mean piston speed until about 8,350 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.796 is long by production standards — less side-load on the cylinder wall and gentler piston acceleration around TDC, the geometry that tolerates high RPM. Each of the 8 cylinders displaces 36.1 ci (592 cc).
11.6:1 is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 12 engines in the Ford 289ci family, all of them 289 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 289 ci / 4.7 L |
|---|---|
| Bore | 4" |
| Stroke | 2.87" |
| Cylinders | 8 |
| Compression ratio | 11.6:1 |
| Rod length | 5.155" |
| Rod ratio | 1.796 |
| Bore/stroke ratio | 1.394 |
| Piston deck clearance | 0.0015" |
| Induction | 1-4 |
|---|---|
| Advertised HP | 271 hp |
| Years | 1965 |
| Bore/stroke character | 1.394 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,870 ft/min — conservative for a street engine |
| Rod ratio | 1.796 — long — less side loading on the cylinder wall, favours high RPM |
| Displacement per cylinder | 36.1 ci |
| Static compression | 11.6:1 — high enough that pump premium or better is normally required |
| Intake valve diameter | 1.783" |
|---|---|
| Exhaust valve diameter | 1.457" |
| Chamber volume | 47.7 cc |
| Rocker ratio | 1.6:1 |
| Lifter type | mechanical |
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