The 5.7L LS6 is the most powerful Gen. 3 small block engine as it came from the factory. It is an improved version of the LS1 produced for the 2001 Z06 Corvette.
The LS6 powered the 2001-04 Corvette Z06 and the 2004-05 Cadillac CTS-V.
Mechanically similar, General Motors’ LS and LS-based Vortec engines wound up on almost every branch of the GM family tree: Chevy, Pontiac, GMC, Cadillac, Buick—heck, even Saab, Hummer, and Isuzu got some LS love.
Since LS and Vortec engines are so common, they’ve become the go-to performance and swap engines of the modern era.
These motors are capable of making a lot of horsepower, and respond well to upgrades like turbos, superchargers, high-flow cylinder heads, intake systems, cams, and nitrous oxide.
The aftermarket is strong, crate engines are available, and used motors are often cheaply sourced through junkyards.
Summit Racing has created a series of comprehensive guides for each engine in the LS family, so engine builders and tuners can have a handy reference for their projects.
This specific guide is for the GM LS6 engine.
[Looking to upgrade your LS6 engine? Check out LS6 Engine Upgrade Guide: Expert Advice for LS6 Mods to Maximize Performance.]
You can see all of our LS engine spec guides and LS-related information here.
(Summit Racing’s Brian Nutter and Paul Spurlock contributed to this article.)
Chevy LS6 Engine Specs
LS6 Performance Specifications
| Engine Ratings | |
|---|---|
| Compression Ratio | 10.5:1 |
| Horsepower Rating | 385-405 hp |
| Torque Rating | 385-400 ft./lbs. |
LS6 Applications
| VIN 8th Digit | Year | Make | Model |
|---|---|---|---|
| S | 2001-04 | Chevy | Corvette Z06 |
| S | 2004-05 | Cadillac | CTS-V |
LS6 Engine Blocks
| LS6 Block Specs | |
|---|---|
| Casting Number | 12561168 |
| Material | Aluminum - Sand Cast |
| Displacement | 5.7L / 346 cid |
| Bore Dia. | 3.898 in. |
| Stroke | 3.622 in. |
| Deck Height | 9.240 in. |
| Bore Spacing | 4.400 in. |
| Thrust Bearing Location | #3 Main |
| Main Cap Style | 6-Bolt |
| Main Housing Bore Dia. | 2.751 in. |
| Cam Housing Bore Dia. (2002-03) | Bore 1/5 = 2.326, Bore 2/4 = 2.317, Bore 3 = 2.307 |
| Cam Housing Bore Dia. (2003-04) | Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307 |
| Cam-to-Crank Centerline | 4.914 in. |
LS6 Rotating Assembly
| LS6 Rotating Assembly Specs | |
|---|---|
| Piston Material | Hypereutectic Cast Aluminum Alloy M142 |
| Piston Style | Flat Top |
| Piston Volume | 0cc |
| Wrist Pin Dia. (2001-late 2004) | 0.9449 in (Press Fit) |
| Wrist Pin Dia. (Late 2004-05) | 0.9435 in (Full Floating) |
| Connecting Rod Material | Powdered Metal |
| Connecting Rod Style | I-Beam |
| Connecting Rod Length | 6.098 in. |
| Connecting Rod Bolts | M9 x 1 x 43 |
| Crankshaft Material | Cast Iron |
| Crankshaft Main Journal | 2.559 in. |
| Crankshaft Rod Journal | 2.100 in. |
| Reluctor Wheel | 24X |
| Flywheel Mounting Flange | 0.857 in. |
LS6 Cylinder Heads
| LS6 Cylinder Head Specs | |
|---|---|
| 2001-04 Casting Numbers | 12564243 |
| Material | Aluminum |
| Combustion Chamber Volume | 65cc |
| Intake Port Shape | Cathedral |
| Intake Runner Volume | 210cc |
| Exhaust Port Shape | D-Port |
| Exhaust Runner Volume | 75cc |
| Intake Valve Diameter | 2.000 in. |
| Exhaust Valve Diameter | 1.550 in. |
| Cylinder Head Bolt Style | Torque to Yield (TTY) |
| Cylinder Head Bolt Size 1997-2003 | (8) M11 x 2 x 155, (2) M11 x 2 x 100, (5) M8 x 1.25 x 45 |
| Cylinder Head Bolt Size 2004 | (10) M11 x 2 x 100, (5) M8 x 1.25 x 45 |
LS6 Cam Specifications
| Year | Model | Int. Duration @.050 | Exh, Duration @.050 | Int. Lift | Exh. Lift | Lobe Separation |
|---|---|---|---|---|---|---|
| 2001 | Corvette Z06 | 204° | 211° | 0.525" | 0.525" | 116° |
| 2002-04 | Corvette Z06 | 204° | 218° | 0.555" | 0.551" | 117.5° |
LS6 Valvetrain
| LS6 Valvetrain Specs | |
|---|---|
| Lifter Style | Hydraulic Roller |
| Lifter Link Style | Plastic Lifter Tray |
| Lifter Body Diameter | 0.842 in. |
| Pushrod Length | 7.385 in. |
| Rocker Arm Mounting Style | Pedestal |
| Rocker Arm Style | Die-Cast, Roller Fulcrum |
| Rocker Ratio | 1.7 |
| Rocker Offset | None |
| Valve Spring Style | Beehive |
| Valve Spring Color | Blue (2001), Yellow (2002-04) |
| Valve Spring Pressure | Yellow = 90 lbs. Seat / 260 lbs. Open |
| Valve Angle | 15 Degrees |
| Intake Valve Material | Steel - Solid Stem |
| Intake Valve Dia. | 2.000 in. |
| Exhaust Valve Material | Steel - Sodium Filled Stem |
| Exhaust Valve Dia. | 1.550 in. |
Other Key LS6 Specs
| Throttle Body, Fuel Injectors, Oil Pan Specs & More | |
|---|---|
| Intake Manifold | LS6 |
| Throttle Body | 78mm, 3-Bolt |
| Throttle Control | Electronic, Drive-by-Wire |
| Fuel Injector Flow | 30 lbs./hr. |
| Fuel Injector Length (between O-Rings) | 2.5 in. |
| Fuel Injector Connector | EV1 |
| PCM | Warren |
| Crankshaft Reluctor Ring | 24x |
| Camshaft Sensor | Rear Mount, 1x on Cam |
| Oil Pan Corvette | Bat Wing, Rear Sump |
| Oil Pan CTS-V | Rear Sump |
| Oil Pump | Standard Volume |
…
NOTE: You can find engine specs and detailed engine upgrade advice for every LS and LS-based Vortec truck engine in one place: The Definitive Guide to LS Engine Specs and LS Engine Upgrades.
Great article!
Thanks
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That’s a good question that may have a few answers. If we’re opining out loud here, it could be that, when compared to the LS engines, Cadillac’s own Northstar V8s weren’t making much power naturally aspirated. In a contemporary XLR, the 4.6L was making a bit north of 300 hp (though the supercharged 4.4L Northstar was well over 400 hp). So when equipping its V-series cars for the luxury performance battle, the Corvette-sourced LS6 engine may have been the best choice.
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