Bore, stroke, displacement and compression for all 6 Ford Flathead V8 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 221–239.4 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.063–3.188" |
| Stroke | 3.750" |
| Compression | 5.5:1 |
| Advertised power | 65–132 hp |
| Years | 1932–1955 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| Flathead 239 | 239.4 ci | 3.1875" × 3.75" | — | — |
| Truck V-8 | 239.4 ci | 3.1875" × 3.75" | — | 106 |
| Power King V-8 | 239.4 ci | 3.1875" × 3.75" | — | 130–132 |
| Flathead 221 | 221 ci | 3.0625" × 3.75" | — | — |
| Flathead V8 221 | 221 ci | 3.0625" × 3.75" | — | 75 |
| Flathead V8 221 | 221 ci | 3.0625" × 3.75" | 5.5:1 | 65 |
Stroke is constant at 3.75" across the family — the displacement spread comes from bore, so these share a crank and differ in the block.
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.