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Ford 97ci specs: 97 ci (1.6L) 4-cylinder, 3.188 x 3.063 in (81 x 77.8 mm) bore and stroke, 8.84:1 compression. Rated 54-75 hp, 1971–1972.
The Ford 97ci is close to square: 3.188" bore against 3.063" stroke, within 4.1%, which splits the difference between a high-revving layout and a torque layout. The 3.063" stroke does not reach 4,000 ft/min of mean piston speed until about 7,850 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.696 is in the range most production engines fall in. Each of the 4 cylinders displaces 24.3 ci (397 cc).
8.84:1 is low by modern standards and generally happy on regular pump fuel.
2 factory variants share these dimensions, rated from 54 to 75 hp across 1971–1972.
| Displacement | 97 ci / 1.6 L |
|---|---|
| Bore | 3.188" |
| Stroke | 3.063" |
| Cylinders | 4 |
| Compression ratio | 8.84:1 |
| Rod length | 5.194" |
| Rod ratio | 1.696 |
| Bore/stroke ratio | 1.041 |
| Piston deck clearance | 0.005" |
| Induction | 1-1 |
|---|---|
| Advertised HP | 54–75 hp |
| Years | 1971–1972 |
| Bore/stroke character | 1.041 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,063 ft/min — conservative for a street engine |
| Rod ratio | 1.696 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 24.3 ci |
| Static compression | 8.84:1 — low by modern standards, generally happy on regular pump fuel |
| Intake valve diameter | 1.507" |
|---|---|
| Exhaust valve diameter | 1.244" |
| Rocker ratio | 1.54:1 |
| Lifter type | mechanical |
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These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1971 | 75 hp | — |
| 1972 | 54 hp | — |