General Motors LS-based small-block engine
The General Motors LS-based small-block engines are a family of V8 and V6 engines designed and manufactured by American automotive company General Motors. First introduced in 1997, the family is a continuation of the earlier first- and second-generation Chevrolet small-block engine, of which over 100 million have been produced altogether, and is also considered to be one of the most popular V8 engines ever. Spanning three generations, a new, sixth generation is expected to enter production soon. Various small-block V8s were and still are available as crate engines.
| General Motors LS small-block engine | |
|---|---|
An LS1 engine in a 1998 Chevrolet Camaro | |
| Overview | |
| Manufacturer | General Motors |
| Designer | Tom Stephens Ed Koerner |
| Production | 1997–present |
| Layout | |
| Configuration | 90° V8, 90° V6 |
| Displacement | 293–511 cu in (4.8–8.4 L) |
| Cylinder bore | 3.78–4.185 in (96.0–106.3 mm) |
| Piston stroke | 3.3–4.125 in (83.8–104.8 mm) |
| Cylinder block material | Aluminum Cast iron |
| Cylinder head material | Aluminum Cast iron |
| Valvetrain |
|
| Compression ratio | 9.08:1–13.1:1 |
| Combustion | |
| Fuel system | Fuel injection, carburetors |
| Fuel type | Gasoline, E85 |
| Oil system | Wet sump, Dry sump |
| Cooling system | Water-cooled |
| Output | |
| Power output | 255–755 hp (190–563 kW) |
| Torque output | 285–715 lb⋅ft (386–969 N⋅m) |
| Dimensions | |
| Dry weight | 402–464 lb (182–210 kg) |
| Chronology | |
| Predecessor | Chevrolet small-block engine (first and second generation) |
| Successor | Chevrolet Gemini small-block engine |
The "LS" nomenclature originally came from the first engine of the Gen III engines, the LS1, which was fitted in the Chevrolet Corvette (C5). The Regular Production Option (RPO) code of the engine, LS, has since been used to generally refer to all Gen III and Gen IV engines; however, Gen V engines are generally referred to as "LT" small-blocks. This can sometimes be misleading, as not all engine RPO codes in the three generations begin with LT or LS. LS and LT engines have powered every single generation of the Corvette since the C5, with the exception of the Z06 variant of the eighth generation Corvette, which is powered by an unrelated small-block engine, the Chevrolet Gemini small-block engine. Various other General Motors automobiles have been powered by LS- and LT-based engines, including trucks such as the Chevrolet Silverado, sports cars such as the Holden Commodore, and SUVs such as the Cadillac Escalade.
A clean-sheet design, the only shared components between the Gen III engines and the first two generations of the Chevrolet small-block engine are the connecting rod bearings and valve lifters. However, the Gen III and Gen IV engines were designed with modularity in mind, and several engines of the two generations share a large number of interchangeable parts. Gen V engines do not share as much with the previous two, although the engine block is carried over, along with the connecting rods. The serviceability and parts availability for various Gen III and Gen IV engines have made them a popular choice for engine swaps in the car enthusiast and hot rodding community, and sometimes is known colloquially as an LS swap. These engines also enjoy a high degree of aftermarket support due to their popularity and affordability.