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The same engine also has a main page: Chevrolet L39.
GMC L39 specs: 267 ci (4.4L) 8-cylinder, 3.50 x 3.484 in (88.9 x 88.5 mm) bore and stroke, 8.3:1 compression. Built 1979–1981.
The GMC 267ci (L39) is close to square: 3.5" bore against 3.484" stroke, within 0.5%, which splits the difference between a high-revving layout and a torque layout. The 3.484" stroke puts mean piston speed at 4,000 ft/min around 6,900 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.636 is in the range most production engines fall in. Each of the 8 cylinders displaces 33.4 ci (547 cc).
8.3:1 is low by modern standards and generally happy on regular pump fuel.
2 factory variants share these dimensions across 1979–1981.
| Displacement | 267 ci / 4.4 L |
|---|---|
| Bore | 3.5" |
| Stroke | 3.484" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.3:1 |
| Rod length | 5.7" |
| Rod ratio | 1.636 |
| Bore/stroke ratio | 1.005 |
| Fuel type | gas |
|---|---|
| Years | 1979–1981 |
| Bore/stroke character | 1.005 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,484 ft/min — conservative for a street engine |
| Rod ratio | 1.636 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 33.4 ci |
| Static compression | 8.3:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| 1979 | — | L39 |
| 1981 | — | L39 |
8 factory vehicles, 1979–1982. Each year opens that model's engine table.