See other engines in this family
Ram Cummins 6.7 High Output specs: 408 ci (6.7L) 6-cylinder, 4.213 x 4.882 in (107 x 124 mm) bore and stroke. Rated 430 hp, 2025–2026.
The Ram Cummins 6.7 High Output is undersquare — the 4.8819" stroke exceeds the 4.2126" bore by 13.7% — a layout that trades peak RPM for leverage and torque low in the range. With a 4.8819" stroke, mean piston speed reaches 4,000 ft/min at only 4,900 RPM — the practical ceiling for a production bottom end — which is why a stroke this long makes its power low and runs out of safe revs early. Each of the 6 cylinders displaces 68.0 ci (1,114 cc).
It is one of 5 engines in the Cummins ISB family, all of them 408 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 430 hp across 2025–2026.
| Displacement | 408 ci / 6.7 L |
|---|---|
| Bore | 4.2126" |
| Stroke | 4.8819" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 0.863 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | diesel |
| Advertised HP | 430 hp |
| Years | 2025–2026 |
| Bore/stroke character | 0.863 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 4,882 ft/min — above the 4,500 ft/min mark where most production bottom ends are considered at their limit |
| Displacement per cylinder | 68.0 ci |
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 |
|---|---|---|
| 2025 | 430 hp | Cummins 6.7 High Output |
| 2026 | 430 hp | Cummins 6.7 High Output |