American Motors 290ci specs: 3.75 x 3.28 in (95.3 x 83.3 mm) bore and stroke, shared by all 4 versions. Displacement, compression and factory ratings.
| Displacement | 290 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.750" |
| Stroke | 3.280" |
| Compression | 9.0–10.0:1 |
| Advertised power | 200–225 hp |
| Years | 1966–1969 |
| Cylinder head data | 2 of 4 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| American Motors 290ci · 3.750" × 3.280" · 9:1 | 290 ci | 3.75" × 3.28" | 9:1 | 200 |
| American Motors 290ci · 3.750" × 3.280" · 10:1 | 290 ci | 3.75" × 3.28" | 10:1 | 225 |
| American Motors 290ci · 3.75" × 3.28" · 9:1 | 290 ci | 3.75" × 3.28" | 9:1 | 200 |
| American Motors 290ci · 3.75" × 3.28" · 10:1 | 290 ci | 3.75" × 3.28" | 10:1 | 225 |
All are oversquare — bore larger than stroke, which favours revs over low-end torque.
Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.