LS Engines

LQ4 Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

GM 6.0L LS LQ4 Engine Specs

The LQ4 is a 6.0L LS (Gen. 3) small block engine used in GM trucks between 1999 and 2007. For marketing purposes, it was also known as the Vortec 6000. The engine specs and information listed here is for the stock LQ4 engine.

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 guide is specifically for the GM LQ4 engine.

[Looking to upgrade your LQ4 engine? Check out LQ4/LQ9 Engine Upgrade Guide: Expert Advice for LQ4 & LQ9 Mods to Maximize Performance.]

You can explore all of our LS engine spec guides and LS tech resources here.

(Summit Racing’s Brian Nutter and Paul Spurlock contributed to this article.)

Chevy LQ4 Engine Specs

LQ4 Performance Specifications

Engine Ratings
Compression Ratio9.4:1
Horsepower Rating300-330 hp
Torque Rating360-370 ft./lbs.

LQ4 Applications

VIN 8th DigitYearMakeModel
U1999-04ChevySilverado 2500
U2001-07ChevySilverado 1500 HD
U2001-07ChevySilverado 2500 HD
U2001-07ChevySilverado 3500
U2002-04GMCSierra 1500 Denali
U2001-06GMCSierra 1500 HD (+2007 Classic)
U1999-04GMCSierra 2500
U2001-06GMCSierra 2500 HD (+2007 Classic)
U2001-06GMCSierra 3500 HD (+2007 Classic)
U2001-06GMCYukon Denali, XL1500, XL2500

LQ4 Engine Blocks

LQ4 Block Specs
Casting Numbers12551364, 12573581, 12577184
Displacement6.0L / 364 c.i.d.
Bore Dia. 4.000 in.
Stroke3.622 in.
Deck Height9.230 - 9.240 in.
Bore Spacing4.400 in.
Thrust Bearing Location#3 Main
Main Cap Style6-Bolt
Main Housing Bore Dia.2.751 in.
Cam Housing Bore Dia. (1999-2003)Bore 1/5 = 2.326, Bore 2/4 = 2.317, Bore 3 = 2.307
Cam Housing Bore Dia. (2003-07)Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307
Cam-to-Crank Centerline4.914 in.

LQ4 Rotating Assembly

LQ4 Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston StyleDished
Piston Volume+ 6.7cc
Wrist Pin Dia.
0.9447 in., 0.9448 in.
(Press Fit)
Wrist Pin Dia.
0.9429 in., 0.9431 in. (Full Floating)
Connecting Rod MaterialPowdered Metal
Connecting Rod StyleI-Beam
Connecting Rod Length6.098 in.
Connecting Rod BoltsM9 x 1 x 43
Crankshaft MaterialCast Iron
Crankshaft Main Journal2.559 in.
Crankshaft Rod Journal2.100 in.
Reluctor Wheel24X
Flexplate/Flywheel Mounting Flange (1999-2000)1.250 in.
Flexplate/Flywheel Mounting Flange (2001-07)0.857 in.

LQ4 Cylinder Heads

LQ4 Cylinder Head Specs
Casting Numbers373, 873317, 035
Combustion Chamber Volume71cc71cc
Intake Port ShapeCathedralCathedral
Intake Runner Volume200cc210cc
Exhaust Port ShapeOvalD-Port
Exhaust Runner Volume70cc75cc
Intake Valve Diameter2.000 in.2.000 in.
Exhaust Valve Diameter1.550 in.1.550 in.
Cylinder Head Bolt StyleTorque to Yield (TTY)Torque to Yield (TTY)
Cylinder Head Bolt Size 1999-2003(8) M11 x 2 x 155, (2) M11 x 2 x 100, (5) M8 x 1.25 x 45
Cylinder Head Bolt Size 2004-07(10) M11 x 2 x 100, (5) M8 x 1.25 x 45

LQ4 Cam Specifications

Duration @ .050 in. (int./exh.)191/190196/207
Valve Lift (int./exh.)0.457 in./0.466 in.0.467 in./0.479 in.
Lobe Separation Angle114°116°
Cam Gear Attachment3-Bolt3-Bolt

LQ4 Valvetrain Specs

LQ4 Valvetrain Specs
Lifter StyleHydraulic Roller
Lifter Link StylePlastic Lifter Tray
Lifter Body Diameter0.842 in.
Pushrod Length7.385 in.
Rocker Arm Mounting StylePedestal
Rocker Arm StyleDie-Cast, Roller Fulcrum
Rocker Ratio1.7
Rocker OffsetNone
Valve Spring StyleBeehive
Valve Spring ColorNatural
Valve Angle15 Degrees
Intake Valve MaterialSteel - Solid Stem
Intake Valve Dia.2.000 in.
Exhaust Valve MaterialSteel - Solid Stem
Exhaust Valve Dia.1.550 in.

Other Key LQ4 Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldTruck Style
Throttle Body80mm, 3-Bolt
Throttle Control (1999-02)Cable-Operated
Throttle Control (2003-04)Electronic, Drive-by-Wire (for most models)
Fuel Injector Flow24.8 lbs./hr.
Fuel Injector Length (between O-Rings)1.9 in.
Fuel Injector ConnectorEV6
Crankshaft Reluctor Ring24x
Camshaft SensorRear Mount, 1x on Cam
Oil Pan
Deep Rear Sump
Oil PumpStandard 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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  2. sherrill lance says:

    Thank you very helpfull

  3. Ken Switzer says:

    Thank you very much. I am in the process of adding ls3 heads and boring to 4.065” to convert my 6.0 to a 6.2. I am going to make a cam change to hopefully build an engine to produce a pretty flat power curve for daily driving but help when pulling a 6100 pound travel trailer. The information you provide is invaluable to me.

    • Brad Swanson says:

      Ken, It seems that I am having the same issue as you. I have a 27 ft travel trailer and my 2500 with the 6.0 struggles to get up the mountains here in AZ. My truck has the .411 rear end too so I am also looking for ways to increase hp and torque for easier pulling. I would be interested in more details to what you are doing to your engine to gain that extra umph to pull your rig. Thanks -Brad

      • Tick Street Heat Stg 2 229/244 | .618”/.610” | LSA112+4. Cam, Ls3 heads. Anymore questions feel free to ask.

      • I’m planning on building up my pickups stock LQ4. I’m planning on installing an LS6 cam, either LS6 or 243 cast heads, a Holly 102MM Sniper high rise intake, high output oil pump, and 42 lbs injectors. Will the stock ECM be just fine with all the upgrades or will I need to tune or replace it with one that will? This is my first LS build and I grew up with the first and second gen small blocks. Let me know please, thank you.

        • You will need to tune. especially because you’re drastically upping the flow of the injectors. You’ll probably pay a shop $3-400 or more. Or, for the same price, you can buy the HP Tuners MPVI2, and the credits to tune your truck. If you aren’t computer savvy and detail oriented, maybe someone in your family is. With that tuner and programming you’ll also be set if you want to make changes in the future. Even with a stock engine, you can gain 40+ horsepower with a simple,safe tune(no joke, just by changing GM’s ridiculous power enrichment settings). Botom line, even if your truck still runs ok with the upgrades, you won’t gain much without a tune. Jim

        • Definitely look into Blackbear performance for a tune. Beat money ever spend on my Denali

      • Jason sisson says:

        I’m looking for exact same . Mines 2000 6.0 2500 . All info is very much invaluable too me also

  4. jon kennedy says:

    I am getting ready to do a ls swap to a 1984 1ton dully for pulling trailers and I am try to find the best heads and cam and things to build a very good pulling truck

    • Ls3 heads and Tick Street Heat Stg 2 229/244 | .618”/.610” | LSA112+4 cam. The reason for the cam is ls3 heads are very high flow, therefore a heavier-durable cam is needed. As far as a list for other bolt on upgrades:Choice of exhaust system, performance spark plugs and plug wires, better quality distributor (complete set), cooling fan, better quality oil. These are baseline upgrades that don’t involved SERIOUS time and money.

  5. Raymond Jackson says:

    Very helpful looking forward to turning my lq4 into a race motor for my 67 nova thanks

  6. Thanks for this very detailed information. I too am going to build my LQ4 for my 66 Nova. This info will be helpful.

  7. can i add 40 hp with a simple cam upgrade yo my 2004 6.0 lq4?

  8. Eddie B Foster Jr says:

    everywhere i reed its a compleet top end change, id thought the 04 ls cathedral heads were the good ones… thought id gotten a good deal…, i can aford a cam swap, all i. after is 400 hp or close to… any help would be appreciated i hope i didnt waist my money on this 04 ls lq4.

    • Simple things you could do is change the heads out with ls3 heads, larger cam, add a cold air intake, add an exhaust system- If you look around most manufacturers will provide a range of power increase. Examples; (10-15hp) or (16-21hp).- just try to choose the best one for your budget, higher quality performance;spark plugs, plug wires, distributor (complete set);better, hotter spark gives the truck the ability to burn off more gas when it is in the cylinder, having the truck tuned would definitely help after you add upgrades. Again, simple things that can be done to get you more likely than not to 435-485hp depending on the tune and how well the parts you decide to buy perform.

      • Travis Sehn says:

        Wtf this guy talkin about a distributor in a lq4???? Do u even know what ur talking about? And ls3 heads? Arent they rectangular port? Then u gotta change intake….. this guy givin bad advice piss off noob

  9. Eddie B Foster Jr says:

    by ghe way, im adding headers,x pipe exaust, electric fans, cold air induction id hoped a cam kit with all that eould get me to roughly 400 hp at thd flywheel…..

  10. Danial Miller says:

    I got a 2005 chevy 2500 HD. The manufacturer date is 10/2004.
    I am,curious if the 6.0 has gen 3 or gen 4 rods? Either way is fine, but I would like to know.
    Debating on whether to put it in a 69 Corvette, or a 476 Big Block.
    If anyone can tell me for sure, I would be very grateful.

  11. My LQ4 is an 01 from a Yukon Denali and it is a Drive by Wire. Ran it for 2 years in my 98 Silverado before pulling it to scrap the truck. Even wired up the cruise control from my 98 to the 01 TAC module to work.

  12. I am an owner of a 04′ 2500 Sierra looking to boost HP from factory 300hp to around 380-400hp with Torque increase as well. I am running the LQ4 6.0L engine and I would like to use as much factory product as possible. I am very familiar with Gen I/II small blocks but looking to tackle a new beast and get some pulling power.

    Can I achieve this gain with a cam and heads or should I consider a bore and piston replacement as well. I would like to spend as little as possible but I am willing to do all if needed. How will these changes effect the factory electronics/module and performance?

    Anything is less than buying a new truck and I have an awesome foundation/ truck already.

    • Brian Nutter says:

      Jason, you can hit your target easily with just a cam. The Summit Pro LS truck line has quite a few variants in stages 1 through 4. The Stage 1 high lift (uses factory LS6 springs) is part number SUM-8719. The drop in version of that is SUM-8712. There’s even a specific tow/RV cam meant to maximize torque in the 2500-3500 range called the SUM-8718. They can run with a factory tune, but a tune is heavily recommended. There is a lot of power there along with trans shift points and turning off torque limiting etc. We recommend doing this with your local chassis dyno tuner. The information you get is invaluable an will make it run just like the factory. The heads you have are pretty good. They can be CNC’d and that would put you well over 400 even with a smaller stage 1 cam. Another choice is the Trick Flow As Cast 220’s. those would bump compression a bit too.

  13. Brian Nutter says:

    Folks, I’m seeing quite a bit of misinformation out there about LS3 heads and cam recommendations for trucks etc. Please read this article: In particular, Summit has released a new line of cams called Pro LS. There are tow cams, truck cams, truck performance cams, then finally they get into the automotive lineup. Weight, gear, converter are critical. The following article and video will be of great help in terms of picking a cam and talking with the experts at Summit Racing about which one is best for your application.

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  16. Doug Heyne says:

    I have a 2006 LQ4 in my 3500 Silverado. Curious if the stock LS3 cam would be a good cheap upgrade for pulling, and overall performance.

  17. Pingback: Monte Makeover (Part 6): Summit Racing Pro LS Cam Install, Exhaust Upgrade...and Dyno Test!

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  20. Christopher Almaguer says:

    I’m currently looking into buying a 6.0 for my project 03 Chevy Silverado Single cab that I want to get some speed and power out of and I was wondering if I should buy a 6.0 or get a 5.7 or 5.3

  21. Jerry I have 1969 Chevy truck that is modified I purchase and I not sure what 6L motor and hp is has , I was told a 2005 3/4 Chevy truck I got a F103 number on the front block pass side and pass head alum. 321 205 197 342 319 and the driver side3212f5044363 and oil pan 2577396 can any please help me thanks Jerry

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  23. Can you put ls3 heads on 6.0 without changing anything wit a cam swap

  24. Does anyone know a good throttle body than can go on a tbss intake manifold trying to swap out the regular manifold and throttle body I have on my lq4 now

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  26. Jeff Guimont says:

    I have a 99 silverado 2500 2wd with 6.0 w/ 289K. Wanting to rebuild another 6.0 but use 862 heads to bump up the compression, but, if at all possible not be relegated to using 92 octane. I understand that even with the higher static compression that the cylinder pressure can be managed by cam timing and bleeding off some of the pressure. Bottom line, does anyone have any recommendations for the kind of cam to use? I will be doing some porting work in the heads to increase flow.

    • Jeff, did you ever figure out anything? Wanting to do a similar build, but don’t want to run higher octane fuel either.

  27. Can anyone recommend a good, tunnel type after market EFI intake for an LQ9 that will fit under the stock hood of a BMW Z3?

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