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GMC LLR specs: 223.9 ci (3.7L) 5-cylinder, 3.76 x 4.055 in (95.5 x 103 mm) bore and stroke. Rated 242 hp, 2007–2012. Used in the Chevrolet Colorado. DOHC.
The GMC Vortec 3700 (3.7L I5) (LLR) is undersquare — the 4.0551" stroke exceeds the 3.7598" bore by 7.3% — a layout that trades peak RPM for leverage and torque low in the range. The 4.0551" stroke puts mean piston speed at 4,000 ft/min around 5,900 RPM, which is where a production bottom end is generally considered at its limit. Each of the 5 cylinders displaces 44.8 ci (734 cc).
It is one of 2 engines in the Vortec 3700 (3.7L I5) family, all of them 223.9 ci — the differences between them are in compression, heads and rating, not displacement. 6 factory variants share these dimensions, rated at 242 hp across 2007–2012.
| Displacement | 223.9 ci / 3.7 L |
|---|---|
| Bore | 3.7598" |
| Stroke | 4.0551" |
| Cylinders | 5 |
| Bore/stroke ratio | 0.927 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 242 hp |
| Years | 2007–2012 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2009 | LLR net | 242 @ 5600 * | 242 lb-ft @ 4600 * | — |
| 2010 | LLR net | 242 @ 5600 * | 242 lb-ft @ 4600 * | — |
| 2011 | LLR net | 242 @ 5600 * | 242 lb-ft @ 4600 * | — |
| 2012 | LLR net | 242 @ 5600 * | 242 lb-ft @ 4600 * | — |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 0.927 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 4,055 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 44.8 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 |
|---|---|---|
| 2007 | 242 hp | LLR |
| 2008 | 242 hp | LLR |
| 2009 | 242 hp | LLR |
| 2010 | 242 hp | LLR |
| 2011 | 242 hp | LLR |
| 2012 | 242 hp | LLR |
3 factory vehicles, 2007–2012. Each year opens that model's engine table.