LS6 5.7L engine: specs, donor vehicles & swap notes
The LS6 is a 5.7 L aluminum-block Generation III engine built 2001–2005, rated 385–405 hp. It came in 3 vehicle applications, including Chevrolet Corvette C5 Z06, Cadillac CTS V-Series.
| Spec | Value |
|---|---|
| RPO | LS6 |
| Family | Generation III |
| Years | 2001–2005 |
| Displacement | 5.7 L / 346 ci |
| Horsepower | 385–405 hp |
| Torque | 385–400 lb-ft |
| Bore × stroke | 3.898 × 3.622 in |
| Compression | 10.50:1 |
| Block | aluminum |
| AFM/DOD | No |
| VIN 8th digit | S |
| Reluctor | 24x |
| Throttle | Drive-by-wire |
| Stock cam | 2001 LS6: Duration 204°/211° @.050 in. int./exh.; valve lift 0.525"/0.525" int./exh.; 116° LSA; blue valve springs (90 lbs seat / 260 lbs open); 2002-2004 LS6: Duration 204°/218° @.050 in. int./exh.; valve lift 0.555"/0.551" int./exh.; 117.5° LSA; yellow valve springs (90 lbs seat / 260 lbs open) |
| Firing order | 1-8-7-2-6-5-4-3 |
- Excessive oil consumption via PCV/valley cover. Fix: Top off oil; add catch can; reseal valley-cover PCV baffles.
- Broken valve springs (mostly 2001). Fix: Replace with updated 2002+ springs; inspect for dropped valves.
- Overheating under track/high-power use. Fix: Larger radiator and/or oil cooler.
- Rocker arm bearing failure (early models). Fix: Trunnion upgrade; replace failed rockers.
Aluminum
The LS6 specs above are not yet confirmed against GM documents; GM ratings varied by year and vehicle.
How the LS6 differs from the other 5.7 L Gen III engines
The LS6 is one of the two 5.7 L Gen III engines we list: LS1, LS6. From our engine table:
- Compression 10.50:1, the highest of the group.
- Up to 405 hp from the factory; the LS1 makes up to 382 hp.
- Built 2001–2005.
Swapping the LS6: what to plan for
- Computer: 24x crank, so the LS6 matches a Gen III computer (0411/P01 or P59); an E38 or E67 only reads 58x. Throttle and wiring have to suit the computer too. More: how to wire your LS (the full checklist for your engine and computer).
- Drive-by-wire throttle. Plan on the pedal and throttle body that match the LS6, and a computer that runs drive by wire; the base Holley Terminator X is cable-only (the X Max does drive-by-wire). More: drive-by-wire pinout.
- From a Corvette (Chevrolet Corvette C5 Z06): Corvette spacing, the most compact accessory drive. More: accessory drive spacing.
- From a Cadillac CTS-V: Corvette accessory spacing; the CTS-V has its own oil pan. More: oil pans.
Refresh parts for the LS6
From our Gen III refresh list, the parts that are specific to the LS6. Seals, gaskets and the upgrades worth doing on any Gen III with the engine out are in the full refresh list, next to every torque spec.
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| Part | GM part # | Why for this engine |
|---|---|---|
| Chevrolet Performance LS1/LS6 multilayer head gasket | 12589226 | Listed for the LS6; a new gasket goes on any time the heads come off. |
| GM multi-layer steel LS1/LS6 head gasket set | 12589226 | Listed for the LS6; a new gasket goes on any time the heads come off. |
| Stock cylinder head bolt set, 1997-2003 LS (unequal-length design) | 12498545 | LS6 engines built through 2003 use the first-design, unequal-length bolts. Single use. Engines built from 2004 take the second-design, equal-length set (in the Gen IV list). |
| Chevrolet Performance Gen III LS knock sensor 12589867 (each) | 12589867 | The LS6 has its knock sensors in the valley, under the intake, where water collects. |
| Chevrolet Performance LS Gen III camshaft position sensor 19420911 | 19420911 | 24x engines like the LS6 read the cam at the rear of the block. |
From real tunes: 5.7 L on a Gen III computer
What these settings look like in the 616 naturally aspirated pump-gas tunes for 5.7 L engines on Gen III computers (0411/P01, P59) in our tune library (as of 2026-10-15). Every RPO of this size is pooled, not only the LS6, and so are all cams, heads and builds: that is why the ranges are wide. Use them to spot a value that is far outside what works, not as your numbers.
| Setting | Range | Median | Tunes |
|---|---|---|---|
| Hot idle target | 550 rpm to 925 rpm | 800 rpm | 616 (middle 80%) |
| Warm idle airflow, in gear | 6.2 g/s to 12.9 g/s | 7.4 g/s | 597 (middle 80%) |
| Idle spark (around 800 rpm) | 16° to 28° | 22° | 596 (middle 80%) |
| Power enrichment (PE) lambda | 0.80 to 0.88 | 0.84 | 597 (middle 80%) |
| WOT spark at 5,000 rpm, about 0.9 g/cyl | 15.0° to 27.0° | 22.0° | 597 (middle 80%) |
For starting values matched to your LS6's cam, injectors and fuel, use the turn-on tune builder. Always finish on a dyno, and read our safe tuning limits before any wide-open pass.
Donor vehicles with the LS6
Where to find an LS6 at the junkyard: 3 vehicle applications below. Confirm it from the RPO sticker in the glovebox or the 8th VIN digit (for the LS6: S).
| Vehicle | Years |
|---|---|
| Cadillac CTS V-Series | 2004–2005 |
| Chevrolet Corvette C5 Z06 | 2001–2004 |
| SSC Ultimate Aero TT (modified) | 2007–2008 |
Buying a used LS6
A used LS6 has no single part number, so this page does not link a search. Confirm the engine from the RPO sticker or the 8th VIN digit (for the LS6: S) before you buy.
Next steps
- Plan a swap with the LS6
- Find a cam for the LS6
- What the LS6 tune needs
- Compare every LS donor engine
- Size injectors and fuel pump
- LS torque specs
- Swap guides by vehicle