See other engines in this family
American Motors 250ci (1958–1960) specs: 250 ci 8-cylinder, 3.50 x 3.25 in (88.9 x 82.6 mm) bore and stroke, 8.7:1 compression. Rated 200-215 hp, 1958–1960.
The American Motors 250ci (1958–1960) is oversquare — the 3.5" bore exceeds the 3.25" stroke by 7.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.25" stroke does not reach 4,000 ft/min of mean piston speed until about 7,400 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 31.3 ci (512 cc).
8.7:1 is low by modern standards and generally happy on regular pump fuel.
4 factory variants share these dimensions, rated from 200 to 215 hp across 1958–1960.
| Displacement | 250 ci |
|---|---|
| Bore | 3.5" |
| Stroke | 3.25" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.7:1 |
| Bore/stroke ratio | 1.077 |
| Fuel type | gas |
|---|---|
| Advertised HP | 200–215 hp |
| Years | 1958–1960 |
| Bore/stroke character | 1.077 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,250 ft/min — conservative for a street engine |
| Displacement per cylinder | 31.3 ci |
| Static compression | 8.7:1 — low by modern standards, generally happy on regular pump fuel |
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 | 215 hp | — |
| 1959 | 215 hp | — |
| 1960 | 200 hp | — |
| 1960 | 215 hp | — |
1 factory vehicle, 1958–1960. Each year opens that model's engine table.