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Ford Power Stroke 6.7 specs: 406 ci (6.7L) 8-cylinder, 3.90 x 4.25 in (99.1 x 108 mm) bore and stroke, 16.2:1 compression. Rated 390-500 hp. OHV.
The Ford Power Stroke 6.7 is undersquare — the 4.25" stroke exceeds the 3.9" bore by 8.2% — a layout that trades peak RPM for leverage and torque low in the range. The 4.25" stroke puts mean piston speed at 4,000 ft/min around 5,650 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 50.8 ci (832 cc).
At 16.2:1 this is a compression-ignition engine: the ratio is the heat source that lights the fuel, not a knock limit to be managed.
It is one of 3 engines in the Power Stroke 6.7 family, all of them 406 ci — the differences between them are in compression, heads and rating, not displacement. 5 factory variants share these dimensions, rated from 390 to 500 hp. Factory fitments include the Ford F-250 Super Duty, Ford F-350 Super Duty, Ford F-450 Super Duty and 1 other.
| Displacement | 406 ci / 6.7 L |
|---|---|
| Bore | 3.9" |
| Stroke | 4.25" |
| Cylinders | 8 |
| Compression ratio | 16.2:1 |
| Bore/stroke ratio | 0.918 |
| Block material | compacted graphite iron |
|---|---|
| Head material | aluminum |
| Valvetrain | OHV |
| Fuel type | diesel |
| Advertised HP | 390–500 hp |
| Bore/stroke character | 0.918 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 4,250 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 50.8 ci |
| Static compression | 16.2:1 — high enough that pump premium or better is normally required |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| — | 390 hp | Scorpion Gen 1 |
| — | 440 hp | Scorpion Gen 2 |
| — | 450 hp | Scorpion Gen 3 |
| — | 475 hp | Scorpion Gen 4, Scorpion Gen 5 |
| — | 500 hp | Scorpion Gen 5 H.O. |