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Ram LA 318 specs: 318 ci (5.2L) 8-cylinder, 3.909 x 3.311 in (99.3 x 84.1 mm) bore and stroke. Built 1974–1987. Used in the Dodge Ramcharger. OHV.
The Ram LA 318 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 8 cylinders displaces 39.8 ci (651 cc).
It is one of 13 engines in the Magnum family, sitting between the 226 ci and 488 ci members. 7 factory variants share these dimensions across 1974–1987.
| Displacement | 318 ci / 5.2 L |
|---|---|
| Bore | 3.9094" |
| Stroke | 3.311" |
| Cylinders | 8 |
| Configuration | V8 |
| Bore/stroke ratio | 1.181 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Years | 1974–1987 |
| 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 |
|---|---|---|
| 1974 | — | LA 318 |
| 1975 | — | LA 318 |
| 1983 | — | LA 318 |
| 1984 | — | LA 318 |
| 1985 | — | LA 318 |
| 1986 | — | LA 318 |
| 1987 | — | LA 318 |