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Ram Magnum 3.9 specs: 239 ci (3.9L) 6-cylinder, 3.909 x 3.311 in (99.3 x 84.1 mm) bore and stroke. Rated 175 hp, 1994–2001. Used in the Ram 1500. OHV.
The Ram Magnum 3.9 is oversquare — the 3.9094" bore exceeds the 3.311" stroke by 18.1% — a layout that favors airflow and RPM over leverage at the crank. The 3.311" stroke does not reach 4,000 ft/min of mean piston speed until about 7,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 39.8 ci (653 cc).
It is one of 5 engines in the LA family, the smallest at 239 ci. 8 factory variants share these dimensions, rated at 175 hp across 1994–2001.
| Displacement | 239 ci / 3.9 L |
|---|---|
| Bore | 3.9094" |
| Stroke | 3.311" |
| Cylinders | 6 |
| Configuration | V6 |
| Bore/stroke ratio | 1.181 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 175 hp |
| Years | 1994–2001 |
| Bore/stroke character | 1.181 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,311 ft/min — conservative for a street engine |
| Displacement per cylinder | 39.8 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 |
|---|---|---|
| 1994 | 175 hp | Magnum 3.9 |
| 1995 | 175 hp | Magnum 3.9 |
| 1996 | 175 hp | Magnum 3.9 |
| 1997 | 175 hp | Magnum 3.9 |
| 1998 | 175 hp | Magnum 3.9 |
| 1999 | 175 hp | Magnum 3.9 |
| 2000 | 175 hp | Magnum 3.9 |
| 2001 | 175 hp | Magnum 3.9 |