Shelby 289ci specs: 101.6 x 72.9 mm (4.0000 x 2.8700 in) bore and stroke, shared by all 4 versions. Displacement, compression and factory ratings.
| Displacement | 289 ci |
|---|---|
| Cylinders | 8 |
| Bore | 4.000" |
| Stroke | 2.870" |
| Compression | 11.6–13.0:1 |
| Advertised power | 271–306 hp |
| Years | 1963–1967 |
| Cylinder head data | 4 of 4 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| Shelby 289ci · 4" × 2.87" · 11.6:1 | 289 ci | 4" × 2.87" | 11.6:1 | 271 |
| Shelby 289ci · 4" × 2.87" · 12:1 | 289 ci | 4" × 2.87" | 12:1 | 289 |
| Shelby 289ci · 4" × 2.87" · 12.7:1 | 289 ci | 4" × 2.87" | 12.7:1 | 306 |
| Shelby 289ci · 4" × 2.87" · 13:1 | 289 ci | 4" × 2.87" | 13:1 | 306 |
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.