See other engines in this family
Cadillac Northstar specs: 279 ci (4.6L) 8-cylinder, 3.661 x 3.307 in (93 x 84 mm) bore and stroke, 10.3:1 compression. Rated 275-320 hp. DOHC.
The Cadillac Northstar is oversquare — the 3.6614" bore exceeds the 3.3071" stroke by 10.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.3071" 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 34.9 ci (571 cc).
10.3:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.
It is one of 4 engines in the Northstar family, sitting between the 266.7 ci and 281 ci members. 3 factory variants share these dimensions, rated from 275 to 320 hp. Factory fitments include the Cadillac XLR, Cadillac STS, Cadillac DeVille and 12 others.
| Displacement | 279 ci / 4.6 L |
|---|---|
| Bore | 3.6614" |
| Stroke | 3.3071" |
| Cylinders | 8 |
| Compression ratio | 10.3:1 |
| Bore/stroke ratio | 1.107 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 275–320 hp |
| Bore/stroke character | 1.107 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,307 ft/min — conservative for a street engine |
| Displacement per cylinder | 34.9 ci |
| Static compression | 10.3:1 — 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 |
|---|---|---|
| — | 275 hp | LD8 |
| — | 300 hp | L37 |
| — | 320 hp | LH2 |