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
|Horsepower Rating||385-405 hp|
|Torque Rating||385-400 ft./lbs.|
|VIN 8th Digit||Year||Make||Model|
LS6 Engine Blocks
|LS6 Block Specs|
|Material||Aluminum - Sand Cast|
|Displacement||5.7L / 346 cid|
|Bore Dia.||3.898 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|
|Wrist Pin Dia.|
|0.9449 in (Press Fit)|
|Wrist Pin Dia.|
|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.|
|Flywheel Mounting Flange||0.857 in.|
LS6 Cylinder Heads
|LS6 Cylinder Head Specs|
|2001-04 Casting Numbers||12564243|
|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
|Int. Lift||Exh. Lift||Lobe Separation|
|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|
|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|
|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|
|Crankshaft Reluctor Ring||24x|
|Camshaft Sensor||Rear Mount, 1x on Cam|
|Bat Wing, 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.
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