Bore, stroke, displacement and compression for all 7 Ford 240/300 Big Six engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 240–300 ci |
|---|---|
| Cylinders | 6 |
| Bore | 4.000" |
| Stroke | 3.180–3.980" |
| Compression | 8.8–8.9:1 |
| Advertised power | 115–170 hp |
| Years | 1965–1996 |
| Cylinder head data | 1 of 7 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 300 Six | 300 ci | 4" × 3.98" | — | — |
| 300 Six | 300 ci | 4" × 3.98" | — | 115–120 |
| 4.9L Six | 300 ci | 4" × 3.98" | — | 115–117 |
| 300 Six EFI | 300 ci | 4" × 3.98" | 8.8:1 | 145–150 |
| 300 Big Six | 300 ci | 4" × 3.98" | 8.9:1 | 165–170 |
| 300 Six | 300 ci | 4" × 3.98" | 8.9:1 | 165 |
| 240 Six | 240 ci | 4" × 3.18" | — | — |
Every engine here shares a 4" bore; displacement varies by stroke alone, which is the signature of a family built on one block with different cranks.
1 of 7 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.