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GMC LGX specs: 217 ci (3.6L) 6-cylinder, 3.701 x 3.37 in (94 x 85.6 mm) bore and stroke, 11.5:1 compression. Rated 310 hp, 2017–2023. Used in the GMC Acadia.
The GMC High Feature V6 (LGX) is oversquare — the 3.7008" bore exceeds the 3.3701" stroke by 9.8% — a layout that favors airflow and RPM over leverage at the crank. The 3.3701" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 36.2 ci (593 cc).
11.5:1 on aluminum heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 9 engines in the High Feature V6 family, sitting between the 169 ci and 222.7 ci members. 7 factory variants share these dimensions, rated at 310 hp across 2017–2023.
| Displacement | 217 ci / 3.6 L |
|---|---|
| Bore | 3.7008" |
| Stroke | 3.3701" |
| Cylinders | 6 |
| Configuration | V6 |
| Compression ratio | 11.5:1 |
| Bore/stroke ratio | 1.098 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 310 hp |
| Years | 2017–2023 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2017 | LGX net | 310 @ 6600 * | 271 lb-ft @ 5000 * | — |
| 2018 | LGX net | 310 @ 6600 * | 271 lb-ft @ 5000 * | — |
| 2020 | LGX net | 310 @ 6800 * | 266 lb-ft @ 2800 * | — |
| 2021 | LGX net | 310 @ 6800 * | 266 lb-ft @ 2800 * | — |
| 2022 | LGX net | 310 @ 6800 * | 266 lb-ft @ 2800 * | — |
| 2023 | LGX net | 310 @ 6800 * | 266 lb-ft @ 2800 * | — |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 1.098 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,370 ft/min — conservative for a street engine |
| Displacement per cylinder | 36.2 ci |
| Static compression | 11.5:1 — high enough that pump premium or better is normally required |
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 |
|---|---|---|
| 2017 | 310 hp | LGX |
| 2018 | 310 hp | LGX |
| 2019 | 310 hp | LGX |
| 2020 | 310 hp | LGX |
| 2021 | 310 hp | LGX |
| 2022 | 310 hp | LGX |
| 2023 | 310 hp | LGX |
1 factory vehicle, 2017–2023. Each year opens that model's engine table.