See other engines in this family
Dodge LA 318 specs: 318 ci (5.2L) 8-cylinder, 3.909 x 3.311 in (99.3 x 84.1 mm) bore and stroke. Rated 135-150 hp, 1976–1982. Used in the Dodge Magnum. OHV.
The Dodge 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 Dodge 318ci family, all of them 318 ci — the differences between them are in compression, heads and rating, not displacement. 9 factory variants share these dimensions, rated from 135 to 150 hp across 1976–1982.
| 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 |
| Advertised HP | 135–150 hp |
| Years | 1976–1982 |
| 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 |
|---|---|---|
| 1976 | 150 hp | LA 318 |
| 1977 | 150 hp | LA 318 |
| 1978 | 140 hp | LA 318 |
| 1978 | 150 hp | LA 318 |
| 1979 | 135 hp | LA 318 |
| 1979 | 150 hp | LA 318 |
| 1980 | 135 hp | LA 318 |
| 1981 | 135 hp | LA 318 |
| 1982 | 135 hp | LA 318 |