GM Gen V Engine Guide | LT & EcoTec3 Engine Specs Guide

General Motors’ Gen V LT engines have redefined the classic Chevy small block for the modern era. From pickups to Corvettes, these fifth-generation V8s blend old-school muscle with innovative tech. Buckle up as we journey through the Gen V LT lineup with a look at what makes these engines tick.

The biggest update is GM introduced gasoline direct injection (GDI) across all Gen V V8s. By injecting fuel at over 2,100 psi directly into the combustion chamber, Gen V engines achieve higher compression and better efficiency than older engine designs. For example, the first Gen V, the 6.2L LT1, runs a lofty 11.5:1 compression ratio and helped the 2016 Corvette achieve 460 horsepower while being miserly with the fuel at nearly 29 mpg highway.

Along with direct injection, Gen V (commonly called “LT”) engines feature continuously variable valve timing and Active Fuel Management (cylinder deactivation) to meet modern emissions and fuel economy standards. In short, the Gen V is an evolutionary upgrade of the small block for the 21st century, delivering more power, torque, and efficiency without going away from the trusty pushrod V8 formula.

When GM introduced the Gen V V8s, it gave the truck versions a special name: EcoTec3. This branding underscored the focus on economy and technology in GM’s latest truck engines. The EcoTec3 lineup debuted in the 2014 Chevrolet Silverado 1500 and GMC Sierra 1500, offering two V8 options: a 5.3-liter (code L83, later L84) and a 6.2-liter (L86, later L87). Unlike older Vortec truck blocks, both engines are all-aluminum and pack the full suite of Gen V tech.

The 5.3L EcoTec3 V8 is SAE-certified at 355 hp and 383 lb-ft of torque. Higher compression (around 11.0:1 on regular fuel) and optimized combustion allowed these engines to be both powerful and efficient. Let’s break down each of the V8 EcoTec3 variants and how they differ.

L83 (5.3L EcoTec3 V8)

The L83 is the 5.3-liter Gen V V8 that served as the backbone of GM’s light-duty trucks starting in 2014. With 325 cubic inches of displacement, a 3.78-inch bore and 3.62-inch stroke, the L83 is rated at 355 horsepower and 383 lb-ft of torque in the Silverado/Sierra 1500. It runs a 11.0:1 compression ratio and was designed to run on regular unleaded fuel, making it a great balance of power and economy for a wide range of truck buyers. The L83 features a cast iron crankshaft and hypereutectic aluminum pistons, durable enough for truck duty, though not as exotic as the internals in some high-performance variants.

L86 (6.2L EcoTec3 V8)

If the 5.3L is the workhorse, the L86 6.2L EcoTec3 is the thoroughbred of GM’s truck engine lineup. With 376 cubic inches, a larger 4.065-inch bore, and the same 3.62-inch stroke, the L86 engine takes the Gen V tech to its peak for trucks. It shares much of its DNA with the performance-car LT1 engine (which we’ll discuss later), and in fact beneath the skin the L86 and LT1 are nearly identical. The L86 engine launched with a stout 420 horsepower at 5,600 rpm and 460 lb-ft of torque at 4,100 rpm; tremendous output for a naturally aspirated truck motor. It also runs 11.5:1 compression like the car version, and to achieve those numbers GM generally recommends premium fuel (though the engine can adjust if regular is used, with some loss of power).

Internally, the L86 engine boasts a forged steel crankshaft and larger valves than the 5.3L Gen V engine, breathing through high-flow rectangular ports. The main differences from the car-spec LT1 engine are external and tuning for truck needs. The L86 motor also uses a different intake manifold with longer runners to boost low-end torque, and a deeper oil pan for increased oil capacity (and to suit truck chassis configurations). Its exhaust manifolds are cast iron log-style for durability, as opposed to the tubular headers on a Corvette. These changes optimize the 6.2L Gen V engine for towing and hauling, ensuring that peak torque comes in strong at mid-range RPM.

L86 vs L87 (6.2L EcoTec3 V8)

In 2019, GM introduced the L87 engine as a successor to the L86, coinciding with new truck generations. The L87 6.2L carried over the same impressive 420 hp and 460 lb-ft ratings, but the key upgrade was swapping AFM cylinder deactivation for Dynamic Fuel Management (DFM). DFM is a more advanced system that can shut off any number of cylinders in various combinations, rather than the older system’s fixed half-engine shutdown. This means the L87 engine can run on 8, 6, 4, or even 3 cylinders in certain conditions, constantly adjusting every 125 milliseconds to maximize fuel economy without sacrificing smooth power delivery.

From the driver’s seat, an L87 behaves just like the L86. You still have a burly V8 when you plant your foot, but you’ll notice slightly better mileage and refinement as the engine imperceptibly modulates its cylinder use in the background. With an understanding of the truck-focused EcoTec3 engines, let’s turn to the high-performance side of the Gen V family; the LT engines that have powered Corvettes, Camaros, and more.

The Gen V LT family debuted with the LT1 in the 2014 Corvette Stingray. Since then, the lineup has grown to include naturally aspirated and supercharged variants, and even a radical dual overhead cam version. Here’s a quick overview of the primary LT engines:

• LT1 Engine Specs: 6.2L naturally aspirated V8 (460 hp) used in C7 Corvette and 6th-gen Camaro SS
• LT2 Engine Specs: 6.2L naturally aspirated V8 (495 hp) in the C8 Corvette Stingray, essentially an upgraded LT1 for mid-engine application.
• LT4 Engine Specs: 6.2L supercharged V8 (650 hp) found in the C7 Corvette Z06 and Camaro ZL1.
• LT5 Engine Specs: 6.2L supercharged V8 (755 hp) in the C7 Corvette ZR1, the most powerful of the bunch.
• LT6 Engine Specs: 5.5L naturally aspirated flat-plane-crank V8 (670 hp) in the C8 Corvette Z06, a special high-revving DOHC design.
• There are also a few oddballs like the 6.6L iron-block L8T for HD trucks and specialty crate engines like the LT376/535, but we’ll focus on the main Gen V LT players.

Gen V LT1 Engine Specs and Performance

The LT1 engine is the cornerstone of the Gen V LT family. When it premiered in the 2014 C7 Corvette Stingray, it was hailed as “the most significant redesign in the small block’s nearly 60-year history.” The LT1 produces 460 horsepower and 465 lb-ft of torque (with performance exhaust) in the Corvette, a huge leap from the previous Gen IV LS3.

Technically, the LT1 introduced several improvements over the previous generation LS engines. The new cylinder heads are a symmetrical port design; meaning identical heads for left and right banks with revised valve placement and a centrally located spark plug to optimize the direct injection spray pattern. The direct injection system (with a cam-driven high-pressure pump) allows precise fuel control and is key to the LT1’s power and efficiency. The LT1 also features Active Fuel Management in certain applications although the Corvette’s manual-trans LT1 did not use AFM. Additionally, the LT1’s variable valve timing uses a single cam phaser to adjust all valves simultaneously to broaden the torque curve.

In terms of construction, the LT1 has a forged steel crankshaft, powder-metal connecting rods, and high-strength aluminum pistons with a special dish shape to accommodate direct injection. It retains the small-block’s signature 2-valve pushrod valvetrain, which keeps it compact and lightweight for its output. How light? Around 550 lbs. fully dressed; surprisingly light when compared to overhead-cam engines of similar output. This makes the LT1 an attractive swap candidate for classic cars, as it delivers big power in a relatively small package.

Gen V LT2 Engine Specs and Performance

When the mid-engine C8 Corvette debuted for 2020, it came with a new LT2 6.2L V8; essentially an evolution of the LT1 tailored for a mid-ship layout. At a glance, the LT2’s basics mirror the LT1, but it received a host of upgrades to deliver more power and to fit within the tighter engine bay behind the passenger cabin. A big one is the dry-sump oiling system that helps maintain optimal oil control even through long, high-G turns. The LT2 engine produces up to 495 horsepower and 470 lb-ft of torque, making it the strongest base Corvette engine ever at launch.

Key upgrades include a more aggressive cam profile and a completely reworked intake and exhaust system to suit the mid-engine Corvette. The intake manifold on the LT2 is low-profile and rotated 180 degrees compared to the LT1 (since the engine sits “backwards” in the car). It has a large 87mm throttle body and a huge intake plenum to help the engine breathe at high RPM. The exhaust manifolds were redesigned for the mid-engine Corvette’s short, high-flow exhaust path. Thanks to these breathing improvements, the LT2’s power band stretches higher and makes peak power at a screaming 6,450 RPM.

Gen V LT4 Engine Specs and Performance

For those who crave immense power, the LT4 engine answers the call. This supercharged 6.2L LT-series engine was introduced in the 2015 Corvette Z06 and later used in the Camaro ZL1 and Cadillac CTS-V (3rd gen). The LT4 is essentially an LT1 with a factory-installed supercharger and the necessary beefed-up internals to handle boost. Its headline figures are 650 horsepower and 650 lb-ft of torque, a jaw-dropping output in 2015 that eclipsed even the previous supercharged LS9. Compression is lowered to 10:1 (from 11.5) to accommodate forced induction, and forged aluminum pistons and forged connecting rods replace the LT1’s hypereutectic pistons and powdered rods, ensuring the bottom end can withstand the power. Check out our full writeup on LS vs LT engine to see how they stack up against each other in a head-to-head comparison.

The supercharger is a key piece of the LT4’s identity. GM chose a relatively compact 1.7L Eaton R1740 TVS supercharger, which has a shorter height to fit under Corvette/Camaro hoods. It delivers approximately 9.4 psi of boost in stock form. The LT4 quickly earned a reputation for monstrous performance. It propels a Corvette Z06 from 0 to 60 mph in under three seconds. Yet it’s civil enough to cruise around town, thanks to modern engine controls.

Gen V LT5 Engine Specs and Performance

If the LT4 is merely “extreme,” the LT5 engine is outright absurd, but in the best way. This 6.2L supercharged LT5 showed up in the C7 Corvette ZR1 beginning in 2019 with dry-sump oiling, and it pushed Gen V performance to the max. Output soared to 755 horsepower and 715 lb-ft of torque, making the C7 ZR1 the most powerful production Corvette in history. The LT5 built upon the LT4’s foundation with a larger supercharger and other mods to support it.

The LT5 uses a 2.65L Eaton TVS blower that’s nearly a full liter bigger than the LT4’s unit. This big blower moves a tremendous volume of air, generating roughly 14 psi of boost. To feed the beast, GM did something unprecedented in a modern small block; the LT5 has dual fuel injection. It retains direct injectors like all Gen V engines but also adds supplemental port fuel injectors in the intake runners. This was necessary because at 750 plus hp, the engine’s fuel demand at high RPM exceeds what the direct injectors alone can supply.

Gen V LT6 Engine Specs and Performance

The Gen V family isn’t all pushrods and superchargers; it also produced a unicorn with the LT6 engine. Debuting in the 2023 Corvette Z06, the LT6 is a 5.5-liter naturally aspirated V8 that breaks the small-block mold by featuring dual overhead camshafts and a flat-plane crankshaft. With an astounding 670 hp at 8,400 rpm and 460 lb-ft of torque at 6,300 rpm, the LT6 holds the title of the most powerful naturally aspirated production V8 in the world. It’s essentially a race-bred engine for the street, owing more to Corvette Racing’s Le Mans program than traditional Chevy small-block lineage.

While it wears an “LT” label, the LT6 shares only the broad goals of the Gen V family (high output, compact size) because its architecture is quite different. The block and heads are aluminum, but with DOHC 32-valve geometry and a flat-plane crank that allows it to scream to an 8,600 RPM redline, it uses a unique 4.104-inch bore and a shorter stroke to achieve 5.5L, enabling those high revs. The compression ratio is 12.5:1, even higher than the LT1. The LT6 engine features exotic materials with titanium connecting rods and intake valves, a dynamically balanced flat-plane crank, and a dry-sump oiling system with multiple scavenging stages to handle track corners. This engine shows GM’s commitment to keeping the Corvette at the forefront, even as the world shifts toward electrification.

The LT1 is rated in the range of 460 hp in Corvette trim, whereas the L86 tops out around 420 hp in trucks. This difference largely comes down to tuning and intake/exhaust design. The LT1’s intake (and camshaft) is optimized for higher RPM power, and the Corvette’s freer-flowing exhaust boosts output. The L86 intake manifold features a long-runner design helping it achieve more torque down low at the slight expense of peak horsepower. Essentially, the truck engine delivers its punch at lower revs, which is ideal for towing and heavy loads, where the LT1 loves to rev a bit more to show its superiority on the track.

The LT engines, on the other hand, are all about performance. They are found in sports cars and performance sedans, where peak horsepower and throttle response take precedence. Thus, LT engines often have more aggressive cams, free-flowing intakes, and exhausts, and sometimes omit fuel-saving features (e.g., the manual-trans LT1 Corvette has no AFM). They usually require premium fuel to hit their advertised performance numbers, whereas EcoTec3 engines are often calibrated to run on regular 87 octane unleaded if needed. Also, the LT range expands into specialty territory: Supercharged models (LT4, LT5) and the exotic flat-plane LT6, which have no equivalents on the truck side.

As GM moves forward, the company has committed nearly a billion dollars to the development of upfit of its factories to produce a Gen VI engine. Given how far we’ve come with the fifth generation engines, we absolutely cannot wait to see what advancements come with Gen VI. But no matter whether you’re a truck fan towing a trailer or a sports car enthusiast carving corners, the Gen V engine has excellent options for everyone.