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Chevrolet LQ5 specs: 121 ci (2.0L) 4-cylinder, 3.50 x 3.15 in (88.9 x 80 mm) bore and stroke. Rated 85-88 hp, 1983–1986. Used in the Chevrolet Cavalier.
The Chevrolet 121ci (LQ5) is oversquare — the 3.5" bore exceeds the 3.15" stroke by 11.1% — a layout that favors airflow and RPM over leverage at the crank. The 3.15" stroke does not reach 4,000 ft/min of mean piston speed until about 7,600 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 30.3 ci (496 cc).
It is one of 3 engines in the Chevrolet 121ci family, all of them 121 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions, rated from 85 to 88 hp across 1983–1986.
| Displacement | 121 ci / 2 L |
|---|---|
| Bore | 3.5" |
| Stroke | 3.15" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9–9.3:1 (published figures vary) |
| Bore/stroke ratio | 1.111 |
| Fuel type | gas |
|---|---|
| Advertised HP | 85–88 hp |
| Years | 1983–1986 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1984 | LQ5 net | 88 @ 4800 | 110 lb-ft @ 2400 | 9.3:1 |
| 1986 | LQ5 net | 85 @ 4800 | 110 lb-ft @ 2400 | 9:1 |
Factory specification sheet.
| Bore/stroke character | 1.111 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,150 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.3 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 |
|---|---|---|
| 1983 | — | LQ5 |
| 1984 | 88 hp | LQ5 |
| 1985 | 85 hp | LQ5 |
| 1986 | 85 hp | LQ5 |
2 factory vehicles, 1983–1986. Each year opens that model's engine table.