(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 Ratio | 11:1 |
| Horsepower Rating | 355-380* hp @ 5,600 rpm |
| Torque Rating | 383-416* ft.-lbs. @ 4,100 rpm |
| *Horsepower and torque ranges account for the difference between gasoline and E85 fuel. | |
L83/L8B Application Information
| VIN 8th Digit | Year | Make | Model |
|---|---|---|---|
| C (L83) | 2014-present | Chevrolet | Silverado |
| C (L83) | 2015-present | Chevrolet | Tahoe |
| C (L83) | 2015-present | Chevrolet | Suburban |
| C (L83) | 2014-present | GMC | Sierra |
| C (L83) | 2015-present | GMC | Yukon |
| C (L83) | 2015-present | GMC | Yukon XL |
| R (L8B) | 2016-Present | Chevrolet | Silverado |
| R (L8B) | 2016-Present | GMC | Sierra |
L83/L8B Engine Block Specs
| L83/L8B Block Specs | |
|---|---|
| Part Number | 12620290 |
| Material | 319-T7 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, 1/2 thrust |
| Main Cap Style | 6-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 Centerline | 4.914 in. |
L83/L8B Rotating Assembly
| L83/L8B Rotating Assembly Specs | |
|---|---|
| Piston Material | Hypereutectic Cast Aluminum Alloy |
| Piston Style | Domed (with reliefs for the exhaust valve and direct injector) |
| Piston Volume | 0cc (net) |
| Wrist Pin Dia. | 0.9431 in. (full floating) |
| Connecting Rod Material | Powdered Metal |
| Connecting Rod Style | I-Beam |
| Connecting Rod Length | 6.098 in. |
| Connecting Rod Housing Bore | 2.225 in. |
| Connecting Rod Bolts | M9 x 1 x 43 |
| Connecting Rod Part Number | 12607475 |
| Crankshaft Material | Cast Iron |
| Crankshaft Part Number (Wet Sump) | 12619781 |
| Crankshaft Main Journal Dia. | 2.559 in. |
| Crankshaft Rod Journal Dia. | 2.100 in. |
| Reluctor Wheel | 58X |
| Harmonic Balancer | Iron |
L83/L8B Cylinder Heads
| L83/L8B Cylinder Head Specs | |
|---|---|
| Casting Number | 12620214 |
| Material | 319-T7 Aluminum |
| Combustion Chamber Volume | 57.6cc |
| Intake Port Shape | Rectangle |
| Intake Runner Volume | 248cc |
| Exhaust Port Shape | Flat Oval |
| Exhaust Runner Volume | 102cc |
| Cylinder Head Bolt Style | Torque to Yield (TTY) |
| Cylinder Head Bolt Size | (10) M12 x 1.75, M8 corner bolts |
L83/L8B Camshafts
| L83/L8B Cam Specs | |
|---|---|
| Part Number | 12619823 |
| Duration @ .050 in. (int./exh.)* | -- |
| Valve Lift (int./exh.)* | -- |
| Lobe Separation Angle* | -- |
| Cam Gear Attachment | 1-Bolt |
| Cam Gear Poles | 4X |
| Active Fuel Management (AFM) | Yes |
| Variable Valve Timing (VVT) | Yes |
| *Specifications currently unavailable. | |
L83/L8B Valvetrain
| L83/L8B Valvetrain Specs | |
|---|---|
| Lifter Style | Hydraulic Roller |
| Lifter Link Style | Plastic Lifter Tray |
| Lifter Body Diameter | 0.842 in. |
| Pushrod Dimensions | 7.85 in. (long) x 0.342 (dia.) |
| Rocker Arm Mounting Style | Pedestal |
| Rocker Arm Style | Die-Cast, Roller Fulcrum |
| Rocker Ratio | 1.8 |
| Rocker Offset | None |
| Valve Spring Style | Beehive |
| Valve Spring Color | Natural |
| Intake Valve Angle | 12.5° / Splayed 2.61° |
| Exhaust Valve Angle | 12.0° / Splayed 2.38° |
| Intake Valve Material | Steel, Solid Stem |
| Intake Valve Dia. | 1.928 in. |
| Exhaust Valve Material | Steel, Sold Stem |
| Exhaust Valve Dia. | 1.556 in. |
| Timing Chain Guide Style | Spring-Loaded Tensioner |
Other Key L83/L8B Specs
| L83/L8B Intake, Throttle Body, Fuel Injector Specs & More | |
|---|---|
| Intake Manifold | Truck Style |
| Throttle Body | 80mm, 4-Bolt |
| Throttle Control | Electronic (Drive-by-Wire) |
| Fuel Injector P/N | 12656932 |
| Fuel Injector Flow* | -- |
| Flex Fuel Capable (E-85) | Yes |
| Computer | E92 |
| Crankshaft Reluctor Ring | 58x |
| Camshaft Sensor Location | Timing Cover |
| Oil Pan | Varies by Application |
| Oil Pump | Variable Displacement |
| *Specifications currently unavailable. | |
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.
hi i need torque spec forhead bolts
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.