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Plymouth LA (1971–1979) specs: 360 ci (5.9L) 8-cylinder, 4.00 x 3.579 in (101.6 x 90.9 mm) bore and stroke. Rated 155-245 hp, 1971–1979.
The Plymouth LA (1971–1979) is oversquare — the 4" bore exceeds the 3.5787" stroke by 11.8% — a layout that favors airflow and RPM over leverage at the crank. The 3.5787" stroke puts mean piston speed at 4,000 ft/min around 6,700 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.711 is in the range most production engines fall in. Each of the 8 cylinders displaces 45.0 ci (737 cc).
It is one of 17 engines in the LA family, the largest at 360 ci. 18 factory variants share these dimensions, rated from 155 to 245 hp across 1971–1979.
| Displacement | 360 ci / 5.9 L |
|---|---|
| Bore | 4" |
| Stroke | 3.5787" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.4–8.8:1 (published figures vary) |
| Rod length | 6.123" |
| Rod ratio | 1.711 |
| Bore/stroke ratio | 1.118 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-8-4-3-6-5-7-2 |
| Advertised HP | 155–245 hp |
| Years | 1971–1979 |
| Bore/stroke character | 1.118 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,579 ft/min — in the range typical of performance street engines |
| Rod ratio | 1.711 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 45.0 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 |
|---|---|---|
| 1971 | — | — |
| 1972 | — | — |
| 1973 | — | — |
| 1974 | — | — |
| 1974 | 180 hp | — |
| 1974 | 245 hp | — |
| 1975 | — | — |
| 1975 | 190 hp | — |
| 1975 | 230 hp | — |
| 1976 | — | — |
| 1976 | 170 hp | — |
| 1976 | 220 hp | — |
| 1977 | — | — |
| 1977 | 155 hp | — |
| 1978 | — | — |
| 1978 | 155 hp | — |
| 1978 | 175 hp | — |
| 1979 | 195 hp | — |
8 factory vehicles, 1971–1979. Each year opens that model's engine table.