The L33 is a 5.3L, Gen. 3 small block engine used in GM trucks between 2005 and 2007.
Although it is a truck engine, it used cylinder heads closely related to the LS2 and LS6. The engine came with flat-top pistons for increased compression, and has a unique camshaft.
For marketing purposes, it was known as the Vortec 5300 H.O.
The information engine specs and information listed below is for the stock L33 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.
[NOTE: Looking to upgrade your L33? Read: L33 5.3L Engine Upgrade Guide: Expert Advice for L33 Mods to Maximize Performance.]
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 about the GM L33. You can find our other LS engine spec guides and LS-related tech articles here.
(Summit Racing’s Paul Spurlock and Brian Nutter contributed to this article.)
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Chevy L33 Engine Specs
L33 Engine Performance Specifications
| Engine Ratings | |
|---|---|
| Compression Ratio | 9.9:1 |
| Horsepower Rating | 310 hp |
| Torque Rating | 335 ft./lbs. |
L33 Applications
| VIN 8th Digit | Year | Make | Model |
|---|---|---|---|
| B | 2005-07 | Chevy | Silverado 1500, extended cab, 4WD |
| B | 2005-07 | GMC | Sierra 1500, extended cab, 4WD |
L33 Engine Blocks
| L33 Block Specs | |
|---|---|
| Casting Numbers | 12572733 |
| Material | Aluminum |
| Displacement | 5.3L / 325 c.i.d. |
| Bore Dia. | 3.780 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. | Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307 |
| Cam-to-Crank Centerline | 4.914 in. |
L33 Rotating Assembly
| L33 Rotating Assembly Specs | |
|---|---|
| Piston Material | Hypereutectic Cast Aluminum Alloy |
| Piston Style | Flat Top |
| Piston Volume | 0cc |
| Wrist Pin Dia. (2005) | 0.9429 in., 0.9431 in. (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 |
L33 Cylinder Heads
| L33 Cylinder Head Specs | |
|---|---|
| Casting Numbers | 799, 243 |
| 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 | (10) M11 x 2 x 100, (5) M8 x 1.25 x 45 |
L33 Cam Specifications
| L33 Camshaft Specs | |
|---|---|
| Duration @ .050 in. (int./exh.) | 193°/193° |
| Valve Lift (int./exh.) | 0.482 in./0.482 in. |
| Lobe Separation | 116° |
| Cam Gear Attachment | 3-Bolt |
L33 Valvetrain
| L33 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 | Natural |
| Valve Angle | 15 Degrees |
| Intake Valve Material | Steel - Solid Stem |
| Intake Valve Dia. | 2.000 in. |
| Exhaust Valve Material | Steel - Solid Stem |
| Exhaust Valve Dia. | 1.550 in. |
Other Key L33 Specs
| Throttle Body, Fuel Injectors, Oil Pan Specs & More | |
|---|---|
| Intake Manifold | Truck Style |
| Throttle Body | 78mm, 3-Bolt |
| Throttle Control | Drive-by-Wire |
| Fuel Injector Flow | 25.2 lb./hr. @ 58 psi |
| Fuel Injector Length (between O-Rings) | 1.9 in. |
| Fuel Injector Connector | Mini-Delphi / Multec2 |
| Fuel Rail | Returnless |
| PCM | Warren |
| Crankshaft Reluctor Ring | 24x |
| Camshaft Sensor | Rear Mount, 1x on cam |
| Oil Pan | Rear Deep Sump |
| Oil Pump | Standard Volume |
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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.
[…] L33 […]
L33 should be listed as a 58x crankshaft reluctor ring. My ’06 Silverado w/L33 has the grey sensor, which means the 58x ring. This may mean the L33 used the 24x in the ’05 trucks. I don’t know for sure. I do know what my truck has, though.
☝ You are correct
Probably LH6 in 2006
Paul, with the L33 being a Gen. 3 engine, it would be 24x. One way to confirm this is by checking for driver’s side mounted (rather than in the valley) knock sensors and the cam sensor in the front cover as found on Gen. 4 engines. L33 vehicles were VIN B is the 8th character of the VIN. As Aaron pointed out, if you have a LH6-it would be VIN M. Let us know what you find. We do find odd things all the time, but let’s rule out Generation question first.
It doesn’t matter whether you call it Gen 3 or 4, I can tell you with 100% certainty like Paul said the L33 in a 2006 Model Silvy has the 58x reluctor. I hear what you are saying and yes typically Gen 3 Vortec/LS stuff is 24x but the L33 they used in the 2006 models at least I can say is a 58x, not sure about the 2005 L33’s.
2006 must be a cross over year because the L33 that I pulled myself from a 2006 Silverado is absolutely 100% a 24x crank.
What are the best add on at low to medium money what kind hp can i get out of my 2006 L33 TRUCK BEFORE TEARING IT DOWWN ?????
open up the choke points. Heads and cam is usually the best bang for the buck. A good set of reworked heads can make even a baby cam grow some nads.
Bump the valves up a couple of sizes 2.02 intake and 1.6 exh with 1.7 ratio rockers and clean up the ports. Let that sucker breath.
From 2.0 to 2.02 on the valve makes THAT much difference? point 02??
WELL STEVE GOT THAT SORT OF PLAN TO DO MY 2006 L33 . GOING TO PUT HEADERS AND 2 AND HALF PIPES AND A H PIPE IN HALF WAY SO I THINK IT WILL BE FLOWING THE EXHUAST OUT OF IT. WITH A COLD AIR INTAKE PLUS I HEARD OF PUTTING A 5 IN. ELECTRIC FAN IN THE COLD AIR INTAKE THAT COULD MAKE 15 PSI BOOST TO IT ATHER THE MASS FLOW SENSOR HOOK IT TO BATTERY WITH TOOGLE SWICH AND BOOST PSI GAUGE IN CAB TO SOME BOOSTED FLOW OF AIR INTO MOTOR. PLUS A TUNER COMPUTER CHIP FOR DEGREEING THE CAM AMD FUEL AIR FLOW TO PEAK HP.DON’T KNOW YET BUT PLAN DOING THIS WINTER IN THE BASEMENT ??? WHAT KIND OF HP ?? GAIN YOU THINK I WILL PICK WITHOUT TOUNCHING THE MOTOR OR CAM ???? I WILL LET YOU GUYS KNOW WHEN THIS DISABLED 58 YR. OLD DRAG RACER GETS HER DONE !!! LET WHAT YOU GUYS THINK ABOUT THAT ???? ON A BUGGET WITH CANCER BUT I LOVE RUSH OF A RACE!!!!! NEVER BEATEN ON THE STREET SINCE 6 TEEN LIKE TO GO OUT THAT WAY. DONNIE FROM DECATUR TN.
[…] was known as the Vortec 5300 and made a little less power than its aluminum-block brother, the L33. This was due to the LM4’s smaller intake valve Cathedral port heads, lower compression, and a […]
I’m not to savvy so looking for input on this combination
rebuilt L33 all stock except for LS6 HEADS-MILD CAM. billet double roller timig chain,ARP mainstuds..would LS6 intake work best for 67 Impala w 4L60 trans?
You list the block identification # for the L33 as 12567392. However this is the same identification number found on the iron blocks L59 and LM4. The casting number on my L33 is 12572733 which I beleive to be a 2005 gen 3 block with the black 24x crank sensor
The L33 casting is 12572733. The casting given is what you said. On all cylinders is incorrect.
Hey, thanks for the heads up guys. Looks like you’re right. I’ll make the edit on the chart.
I have an L33 all aluminum engine Gen 4 58 reluctant wheel. HO LS Engine
799 heads. I used a little lunati cam with the aide of fitech. Running 4:10 gears. This is an 1979 Cadillac Seville 4 wheel disc brakes. Power band starts 1800-6400
Still test and tuning. Stay tune for results
Why is this a good engine? Just because its aluminum? Is that really any advantage? Sounds like it takes moola to get horsepower into it—why not just get a larger iron block with a bunch of HP already there? I have not built anything since a bunch of 350 chevies back in the 70s but want to for the fun at age 67.
Aluminum block saves about 100 pounds. If you’ve built 350’s in the ’70’s, back then everybody racing would do everything possible to eliminate EVERY POUND possible… here’s a hundred!
By the way, I’m just browsing through these LS pages and stumbled onto your question, I don’t have an L33 myself–I am on my first LS vehicle, an ’04 Envoy XUV (an Avalanche in sheep’s SUV clothing with an electric roof and isolated cargo area), with an LM4 aluminum 5.3L… Hard to believe I owned Bowtie Supply, a classic auto parts store and speed shop for GM musclecars, mostly Chevys, from about 1986-1999 (RIP…closed due to back/leg problems) and finally driving an LS! I’ve been driving a ZR2 X-cab since ’07!
You should have kept the zr2 and put an LS in it. I have a 2000 zr2 s10 extended cab that I’m swapping an L33 in with a 70mm turbo. Other than the fuel pump, radiator, and electric fans I’ve got pretty much every part to get started. I’ll probably only run 8psi but I know myself well enough to know that I’ll be upping that. 9.9:1 isnt ideal but the L33 is basically the same weight as the iron 4.3L so I wont have to worry with the torsion bars. 200hp just was never enough for a 4000lbs truck so instead of waste money on a newer truck that has basically the same power to weight ratio and is alot weaker built, I just build my vehicles the way GM should have made them. You had a zr2, you know damn well they should have atleast had a 4.8L v8 from the factory. Enjoy your new ride. I’ll be swapping mine for awhile because I’m gonna make sure its factory reliable but makes all the power I want it to.
ive got a 01 zr2 id like to ls swap. wondering what you had to do to get it to fit?
very nice and thorough information, thanks
The L33 is not a gen 3 it’s a gen 4
WRONG. It is Gen III with 24x crank reluctor and center mounted knock sensors. It DOES have many of the same features as the Gen IV aluminum 5.3’s, but is definitely a Gen III
97 to 2007 gen. 3, 2005 to 2020 gen. 4, 2013 to 2021 gen. 5 , the years overlap, The l33 is a gen. 4 I’m building one and this caused me some confusion because when you look up a piston from summit racing for a l33 it will say gen. 4 rod , y’all said it’s a gen. 3 , so I thought that was wrong rod, but the specs matched, so i went to Wikipedia and found out it not a gen. 3 !!!!
Sorry guys i read it wrong, it is a gen 3 , they don’t have Pistons other than the stock ones or ones with lesss compression without changing rod
Can I use blue beehive springs on my L33 rebuild ?
considering the factory ones are beehive…yes.
L33 is a 24xreluctor and you can’t change my mind. Look it up in GM Service Information or the Parts Catalog muppets!
Hmmm…
Just found a L33 that’s being refreshed by someone w/ skills better than I. It’s for a swap, in front of a new old stock Tremec TKO w/ .68 OD 5th. It’s hopefully going into a little reg cab Tacoma five lug (approx 3200 lbs) that’s been lightly lowered on coil-over’s w/ 4 piston StopTech’s that I’m thinking I should upgrade to 6 pistons. Got to whoa sometimes you know! Anyway I have a question with the trans high gear of .68 the 3.73 rear gear and 28.6” rubber the RPM’s (per all the charts I have read) says the engine will be right at 1650 RPM’s @ 55 and 2100 RPM’s @ 70. I’m I over geared? I hope this doesn’t turn into a big debate. Thanks in advance to all!
had a ’68 camaro 3.08 rear saginaw 4 speed. turned 1500 rpm @ 70. Got over 20 mpg. with a 327 that I changed from a 2bbl to a Quadrajet, which I reprogrammed myself. This was in 1973. Yes upgrade the brakes, PLEASE.
Can someone verify that the pushrod length is really .015” smaller than every other 5.3 out there? Everything I can find for push rods is 7.400” and this lists 7.385”. I haven’t gone to measure the ones I have yet but just was curious if anyone else noticed