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Chevrolet LS7 specs: 427 ci (7.0L) 8-cylinder, 4.125 x 4.00 in (104.8 x 101.6 mm) bore and stroke, 11:1 compression. Rated 505 hp. Rod ratio and piston speed.
The Chevrolet LS (LS7) is close to square: 4.125" bore against 4" stroke, within 3.1%, which splits the difference between a high-revving layout and a torque layout. The 4" stroke puts mean piston speed at 4,000 ft/min around 6,000 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 53.4 ci (875 cc).
11:1 on aluminum heads is high enough that pump premium or better is normally required.
It is one of 57 engines in the LS family, sitting between the 293 ci and 454 ci members. Factory fitments include the Chevrolet Corvette C6 Z06, Chevrolet Camaro Z/28.
| Displacement | 427 ci / 7 L |
|---|---|
| Bore | 4.125" |
| Stroke | 4" |
| Cylinders | 8 |
| Compression ratio | 11:1 |
| Bore/stroke ratio | 1.031 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 505 hp |
| Bore/stroke character | 1.031 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 4,000 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 53.4 ci |
| Static compression | 11:1 — high enough that pump premium or better is normally required |
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