Porsche 9A1 specs: 102 x 81.5 mm (4.0157 x 3.2087 in) bore and stroke, shared by all 4 versions. Displacement, compression and factory ratings.
| Displacement | 244–244.1 ci |
|---|---|
| Cylinders | 6 |
| Bore | 4.016" |
| Stroke | 3.209" |
| Compression | 12.9:1 |
| Advertised power | 500–520 hp |
| Years | 2016–2026 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| MA1/76 | 244.1 ci | 4.0157" × 3.2087" | 12.9:1 | 500 |
| 9A1 | 244.1 ci | 4.0157" × 3.2087" | — | 500–520 |
| MA2.75 | 244.1 ci | 4.0157" × 3.2087" | — | 502–518 |
| 40 991 GT3 | 244 ci | 4.0157" × 3.2087" | 12.9:1 | 500 |
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.