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? ReadL33 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.)

Chevy L33 Engine Specs

L33 Engine Performance Specifications

Engine Ratings
Compression Ratio9.9:1
Horsepower Rating310 hp
Torque Rating335 ft./lbs.

L33 Applications

VIN 8th DigitYearMakeModel
B2005-07ChevySilverado 1500, extended cab, 4WD
B2005-07GMCSierra 1500, extended cab, 4WD

L33 Engine Blocks

L33 Block Specs
Casting Numbers12572733
Displacement5.3L / 325 c.i.d.
Bore Dia. 3.780 in.
Stroke3.622 in.
Deck Height9.240 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.Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307
Cam-to-Crank Centerline4.914 in.

L33 Rotating Assembly

L33 Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston StyleFlat Top
Piston Volume0cc
Wrist Pin Dia. (2005)0.9429 in., 0.9431 in. (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

L33 Cylinder Heads

L33 Cylinder Head Specs
Casting Numbers799, 243
Combustion Chamber Volume65cc
Intake Port ShapeCathedral
Intake Runner Volume210cc
Exhaust Port ShapeD-Port
Exhaust Runner Volume75cc
Intake Valve Diameter2.000 in.
Exhaust Valve Diameter1.550 in.
Cylinder Head Bolt StyleTorque 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 Separation116°
Cam Gear Attachment3-Bolt

L33 Valvetrain

L33 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 L33 Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldTruck Style
Throttle Body78mm, 3-Bolt
Throttle ControlDrive-by-Wire
Fuel Injector Flow25.2 lb./hr. @ 58 psi
Fuel Injector Length (between O-Rings)1.9 in.
Fuel Injector ConnectorMini-Delphi / Multec2
Fuel RailReturnless
Crankshaft Reluctor Ring24x
Camshaft SensorRear Mount, 1x on cam
Oil PanRear Deep 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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