Bore, stroke, displacement and compression for all 2 Mitsubishi 4N1 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 138–149 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.386" |
| Stroke | 3.842–4.138" |
| Compression | 14.9–15.5:1 |
| Advertised power | 175–178 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 4N15 | 149 ci | 3.3858" × 4.1378" | 15.5:1 | 178 |
| 4N14 | 138 ci | 3.3858" × 3.8425" | 14.9:1 | 175 |
Every engine here shares a 3.3858" bore; displacement varies by stroke alone, which is the signature of a family built on one block with different cranks.
All are undersquare — stroke larger than bore, favouring torque low in the range.
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.