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Engine Options

GM LS-based Engines and where to find them

We highly recommend using to find an engine at a local junkyard near you. This list on Wikipedia can also provide more information for searching out engines, but may not be completely accurate.

Recommended Engines for Discovery 2 LS Swap Kit


  • 5.3L LM7 iron block: 1999-2007 Chevy Silverado 1500 (VIN Option T), standard 5.3L engine

  • 4.8L LR4 iron block : 2001-2007 Chevy Silverado 1500 (VIN Option V), must be the "short crank" model

  • 5.3L L59 iron block: 2002-2007 Chevy Silverado 1500 (VIN Option Z), flex-fuel 5.3L engine

  • 5.3L LM4 aluminum block: 2003-2004 GMC Envoy XL (VIN Option P), ACE choice for Discovery LS Kit

  • 5.3L L33 aluminum block: 2005-2007 Chevy Silverado 1500 (VIN Option B), high-output, costs more

Gen 3 LS 5.7L and 6.0L engines are compatible electrically and physically, but have not been tested and are not recommended at this time. See page on LS performance. Gen 4 LS and Gen 5 LT engines are not compatible.

Recommended Engines for Discovery 1 LS Swap Kit

  • 4.8L LR4 iron block : 2001-2007 Chevy Silverado 1500 (VIN Option V), must be the "short crank" model

Search Notes:

  • Car-Part will search for multiple common engine years and models, but not necessarily all of the same engine years at one time. Therefore it is useful to do separate searches (first for a 2001 Silverado, second for a 2004 Silverado), to see all possible options.

  • No matter which engine you choose, the ACE Discovery 2 LS Swap Kit requires the use of the drive-by-cable 12200411 "red-blue" PCM commonly found in 2001 Silverado 1500s. This PCM and the associated cable throttle body can be used on all of the engines listed above regardless of original application or model year. More information can be found in the Discovery 2 LS Kit sample parts list. Drive-by-wire PCMs and throttle bodies are not supported at this time.

  • Typically, we think it is more cost effective to just buy the LS engine rather than purchasing an LS "takeout" package with accessories, PCM, and harness or an entire vehicle with an LS. This is because the harness and PCM provided with the package or vehicle may not be the ones the kit requires. This, however, can vary heavily based on pricing.

Other Recommendations:

  • With any used LS engine we often recommend replacing the hard-to-get-to items and common failure points while the engine is out. Typically this includes replacing: rear main seal, oil pan gasket (if not replacing oil pan), knock sensors and the associated sub-harness, spark plugs, water pump, and thermostat.

  • The recommended option for exhaust manifolds is the aftermarket set on the sample parts list. The factory truck and SUV manifolds will not fit the Discovery. Car LS manifolds may fit, but have not been tested.

  • We recommend replacing the oil pan with one of the options specified on the sample parts list. Some have modified the truck oil pan to fit by grinding certain parts. The LM4 engine option will always require a new oil pan because the factory Envoy XL pan is a front sump and will not fit the Discovery.

  • Depending on the model and year of engine, the LS fuel rail may need to be changed. The Discovery uses a returnless fuel system. Some LS engines (typically 2005 and newer) have returnless fuel rails from the factory.

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