See other engines in this family
The same engine also has a main page: Chevrolet LR4.
GMC LR4 specs: 293 ci (4.8L) 8-cylinder, 3.78 x 3.268 in (96 x 83 mm) bore and stroke. Rated 255-285 hp, 1999–2007. Used in the GMC Sierra 1500. OHV.
The GMC 293ci (LR4) is oversquare — the 3.7799" bore exceeds the 3.2677" stroke by 15.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.2677" stroke does not reach 4,000 ft/min of mean piston speed until about 7,350 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 36.6 ci (600 cc).
It is one of 3 engines in the GMC 293ci family, all of them 293 ci — the differences between them are in compression, heads and rating, not displacement. 9 factory variants share these dimensions, rated from 255 to 285 hp across 1999–2007.
| Displacement | 293 ci / 4.8 L |
|---|---|
| Bore | 3.7799" |
| Stroke | 3.2677" |
| Cylinders | 8 |
| Configuration | V8 |
| Bore/stroke ratio | 1.157 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 255–285 hp |
| Years | 1999–2007 |
| Bore/stroke character | 1.157 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,268 ft/min — conservative for a street engine |
| Displacement per cylinder | 36.6 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 |
|---|---|---|
| 1999 | 255 hp | LR4 |
| 2000 | 270 hp | LR4 |
| 2001 | 270 hp | LR4 |
| 2002 | 270 hp | LR4 |
| 2003 | 270 hp | LR4 |
| 2004 | 285 hp | LR4 |
| 2005 | 285 hp | LR4 |
| 2006 | 285 hp | LR4 |
| 2007 | 285 hp | LR4 |