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Chevrolet LS specs: 325 ci (5.3L) 8-cylinder, 3.78 x 3.622 in (96 x 92 mm) bore and stroke, 9.5:1 compression. Rated 270-295 hp. Rod ratio and piston speed.
The Chevrolet LS is close to square: 3.7799" bore against 3.622" stroke, within 4.4%, which splits the difference between a high-revving layout and a torque layout. The 3.622" stroke puts mean piston speed at 4,000 ft/min around 6,650 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 40.6 ci (666 cc).
9.5:1 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 57 engines in the LS family, sitting between the 293 ci and 454 ci members. 2 factory variants share these dimensions, rated from 270 to 295 hp. Factory fitments include the Chevrolet Silverado 1500, GMC Sierra 1500, Chevrolet Tahoe and 3 others.
| Displacement | 325 ci / 5.3 L |
|---|---|
| Bore | 3.7799" |
| Stroke | 3.622" |
| Cylinders | 8 |
| Compression ratio | 9.5:1 |
| Bore/stroke ratio | 1.044 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 270–295 hp |
| Bore/stroke character | 1.044 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,622 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 40.6 ci |
| Static compression | 9.5:1 — 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 |
|---|---|---|
| — | 270 hp | LM7 |
| — | 295 hp | L59 |