LT Engines

L83/L8B 5.3L EcoTec3 Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

L83 EcoTec3 5.3L engine

(Image/General Motors)

This is an engine specification guide for General Motors’ fifth-generation L83 and L8B engines that launched in 2014.

These LT-based engines are commonly referred to as EcoTec3 5.3L engines. They are all-aluminum small blocks, both of which incorporate Active Fuel Management (AFM), Variable Valve Timing (VVT), and are flex-fuel capable (E85). The engines also use direct fuel injection technology, which shoots fuel directly into the combustion chamber instead of the intake runner.

The notable difference between the L83 and L8B engines is that the L8B includes GM’s eAssist powertrain, which combines the traditional gas-powered engine with an electric motor. The eAssist offers an additional:

  • 44 foot-pounds of torque
  • 13 horsepower
  • Up to 12% increased fuel mileage

The L8B also uses stop/start technology that will shut down the engine at traffic lights and during slow, stop-and-go traffic. The engine uses a BAS3 (Belt Alternator Starter) in place of an alternator. The BAS3 recharges the battery AND is used to restart the gas engine after it shuts down. Other than the alternator, both engines use the same major components.

The information listed here is for a stock engine.

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

Chevy L83 & L8B Engine Specs

L83/L8B Performance Specifications

Engine Ratings
Compression Ratio11:1
Horsepower Rating355-380* hp @ 5,600 rpm
Torque Rating383-416* ft.-lbs. @ 4,100 rpm
*Horsepower and torque ranges account for the difference between gasoline and E85 fuel.

L83/L8B Application Information

VIN 8th DigitYearMakeModel
C (L83)2014-presentChevroletSilverado
C (L83)2015-presentChevroletTahoe
C (L83)2015-presentChevroletSuburban
C (L83)2014-presentGMCSierra
C (L83)2015-presentGMCYukon
C (L83)2015-presentGMCYukon XL
R (L8B)2016-PresentChevroletSilverado
R (L8B)2016-PresentGMCSierra

L83/L8B Engine Block Specs

L83/L8B Block Specs
Part Number12620290
Material319-T7 Aluminum
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, 1/2 thrust
Main Cap Style6-Bolt
Main Housing Bore Dia.2.751 in.
Cam Housing Bore Dia.Bore 1/5 = 2.346 in. Bore 2/4 = 2.326 in. Bore 3 = 2.307 in.
Cam-to-Crank Centerline4.914 in.

L83/L8B Rotating Assembly

L83/L8B Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston StyleDomed (with reliefs for the exhaust valve and direct injector)
Piston Volume0cc (net)
Wrist Pin Dia.0.9431 in. (full floating)
Connecting Rod MaterialPowdered Metal
Connecting Rod StyleI-Beam
Connecting Rod Length6.098 in.
Connecting Rod Housing Bore2.225 in.
Connecting Rod BoltsM9 x 1 x 43
Connecting Rod Part Number12607475
Crankshaft MaterialCast Iron
Crankshaft Part Number (Wet Sump)12619781
Crankshaft Main Journal Dia.2.559 in.
Crankshaft Rod Journal Dia.2.100 in.
Reluctor Wheel58X
Harmonic BalancerIron

L83/L8B Cylinder Heads

L83/L8B Cylinder Head Specs
Casting Number12620214
Material319-T7 Aluminum
Combustion Chamber Volume57.6cc
Intake Port ShapeRectangle
Intake Runner Volume248cc
Exhaust Port ShapeFlat Oval
Exhaust Runner Volume102cc
Cylinder Head Bolt StyleTorque to Yield (TTY)
Cylinder Head Bolt Size(10) M12 x 1.75, M8 corner bolts

L83/L8B Camshafts

L83/L8B Cam Specs
Part Number12619823
Duration @ .050 in. (int./exh.)*--
Valve Lift (int./exh.)*--
Lobe Separation Angle*--
Cam Gear Attachment1-Bolt
Cam Gear Poles4X
Active Fuel Management (AFM)Yes
Variable Valve Timing (VVT)Yes
*Specifications currently unavailable.

L83/L8B Valvetrain

L83/L8B Valvetrain Specs
Lifter StyleHydraulic Roller
Lifter Link StylePlastic Lifter Tray
Lifter Body Diameter0.842 in.
Pushrod Dimensions7.85 in. (long) x 0.342 (dia.)
Rocker Arm Mounting StylePedestal
Rocker Arm StyleDie-Cast, Roller Fulcrum
Rocker Ratio1.8
Rocker OffsetNone
Valve Spring StyleBeehive
Valve Spring ColorNatural
Intake Valve Angle12.5° / Splayed 2.61°
Exhaust Valve Angle12.0° / Splayed 2.38°
Intake Valve MaterialSteel, Solid Stem
Intake Valve Dia.1.928 in.
Exhaust Valve MaterialSteel, Sold Stem
Exhaust Valve Dia.1.556 in.
Timing Chain Guide StyleSpring-Loaded Tensioner

Other Key L83/L8B Specs

L83/L8B Intake, Throttle Body, Fuel Injector Specs & More
Intake ManifoldTruck Style
Throttle Body80mm, 4-Bolt
Throttle ControlElectronic (Drive-by-Wire)
Fuel Injector P/N12656932
Fuel Injector Flow*--
Flex Fuel Capable (E-85)Yes
Crankshaft Reluctor Ring58x
Camshaft Sensor LocationTiming Cover
Oil Pan
Varies by Application
Oil PumpVariable Displacement
*Specifications currently unavailable.
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  1. I don’t understand your torque ratings. You list the same number in ft-lbs as Chevy lists in lb-ft, when the ft-lb rating (assuming you are measuring the leverage at the piston wrist pin) would obviously be considerably higher.

    • The torque listed by Chevy is what is listed here, engine torque. And, no, they are not measuring anything at the wrist pin. Hence, the reason the torque numbers are the same…..

  2. hi i need torque spec forhead bolts

    • Al Schrader says:

      Torque until the gasket compresses. Then again in 24 hours after the gasket has stabilized.
      Do not over-torque. Check for leaks. Tighten in a balanced pattern to avoid distorting the gasket surfaces.
      If unsure, go to a junk yard and practice on a similar junk motor. Careful thought will go a long way on this to prevent problems. Suggest recheck for leaks a week later and re-torque if needed. Use common sense for aluminum threads.

      • So how many ft lbs is necessary so i don’t overtorque ??

      • No…TTY bolts .. You TORQUE TO YIELD … You don’t know what you are talking about for this engine. Torque, then specific degree of turn, and these head bolts may have another degree of turn.

  3. Pingback: L82 5.3L EcoTec3 Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More - OnAllCylinders

  4. Pingback: L84 5.3L EcoTec3 Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More - OnAllCylinders

  5. kristi smith says:

    SO what is the engine’stop speed and also I have heard that there is a engine speed governor on these so if that is true like it states in my manual then why is there any information for us consumers to read

  6. Jermaine mosley says:

    There are no cam specs lift lobe or duration why? Is that Secret I’m interested changing the cam but I can’t continue my research properly without the initial numbers

  7. Do the L83 have the same camshaft as the L86?.I build engine for a living.

  8. what are the cam spec on the 2018 truck 1500 5.3 Engine GMC
    thank you for your info.

  9. Brian Watson says:

    sorry that would be the L83 2018 truck 5.3 cam spec. what are they thanks

  10. If you really want to go in depth on the engine info, then add all necessary assembly specs, i.e. head bolts tty specs, rod bolts torque, main bolt torque, intake bolts torque, exhaust, rockers, etc., etc. This would give a more complete piece of information regarding this particular engine.

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