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Mercedes-Benz M120 specs: 6.0L (365 ci) 12-cylinder, 89 x 80.2 mm (3.5039 x 3.1575 in) bore and stroke, 10:1 compression. Built 1992–2002.
The Mercedes-Benz M120 is oversquare — the 3.5039" bore exceeds the 3.1575" stroke by 11.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.1575" stroke does not reach 4,000 ft/min of mean piston speed until about 7,600 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 12 cylinders displaces 30.4 ci (498 cc).
10:1 is in the range that usually runs on pump premium.
It is one of 4 engines in the Mercedes-Benz 365ci family, all of them 365 ci — the differences between them are in compression, heads and rating, not displacement. 11 factory variants share these dimensions across 1992–2002.
| Displacement | 365 ci / 6 L |
|---|---|
| Bore | 3.5039" |
| Stroke | 3.1575" |
| Cylinders | 12 |
| Compression ratio | 10:1 |
| Bore/stroke ratio | 1.11 |
| Fuel type | gas |
|---|---|
| Years | 1992–2002 |
| Bore/stroke character | 1.110 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,158 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.4 ci |
| Static compression | 10:1 — in the range that usually runs on pump premium |
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 |
|---|---|---|
| 1992 | — | M120 |
| 1993 | — | M120 |
| 1994 | — | M120 |
| 1995 | — | M120 |
| 1996 | — | M120 |
| 1997 | — | M120 |
| 1998 | — | M120 |
| 1999 | — | M120 |
| 2000 | — | M120 |
| 2001 | — | M120 |
| 2002 | — | M120 |
2 factory vehicles, 1992–2002. Each year opens that model's engine table.