LS/LT Encyclopedia: Modern GM Small-Block V-8s, Part 3

Welcome to a brief series that charts the evolution and features of the modern GM small-block. This is part three—be sure to check out part one, which includes a quick backstory and then hops into the details of the most ubiquitous V-8 engine family of the 21st century, here. Part two is here, and spans the engines offered from 2005-2015—Ed.

Gen-V: LT Returns with New Tech, DOHC Strikes Back

Engine: LT1

Displacement: 6.2L

Max Power/Torque: 460/465

Model Years: 2014-2024

Domestic Applications: 2014-2019 Corvette Stingray and 2017-2019 Grand Sport, 2016-2024 Camaro SS and 2020-2024 LT1

The third GM V-8 to earn the LT1 moniker came along as an all-new generation of the small-block in the 2014 C7 Corvette. The fifth-gen small-block was based on the same basic architecture as the LS3 it replaced, but had a new block casting and integrated several groundbreaking technologies including direct injection and continuously variable valve timing. Another major difference that’s readily apparent when comparing cylinder heads is a rearranging of the ports, with Gen-V heads looking like a mirror image of their predecessors. A performance dual-mode exhaust was again available on Corvettes, bringing total power to 460/465, while unaltered Camaros were rated at an even 455/455.

Engine: LT4

Displacement: 6.2L (Supercharged)

Max Power/Torque: 682/653

Model Years: 2015-present

Domestic Applications: 2015-2019 Corvette Z06, 2017-2024 Camaro ZL1, 2016-2019 CTS-V, 2022-present Cadillac CT5-V Blackwing, 2022-present Cadillac Escalade-V

The LT4 designation also made an encore appearance in Gen-V, but this time around, it was a lot more than an upgraded LT1. In 2015, this LT4 picked up where the monster LS9 left off two years prior. It carried over with 6.2 liters of displacement but used a smaller (1.7-liter), faster-spinning supercharger that allowed for a lower hood bulge and helped the engine drop 33 pounds in spite of the added one-two tech punch of VVT and direct injection. Upon its introduction, the Z06’s LT4 engine was rated at 650 horsepower with an equal dosage of torque. A new CTS-V would follow in 2016 with a 640/630 tune, followed by the sixth-gen Camaro ZL1 in ’17. Besides its eventual standing as the pinnacle of Camaro development, the ZL1 was noteworthy for getting the full 650/650 motor, thus finally breaking through GM’s long-standing practice of protecting the Corvette’s status with higher horsepower ratings.

2017 also saw Z06 engines upgraded with slightly taller ZL1-style supercharger lids, along with other upgrades aimed at increased cooling. In 2019, an LPO for a performance intake hit the Corvette order guide. This was the first such occurrence since the famed “Airbox” ‘Vettes of 1957, and while GM didn’t recertify the engine, internally, they claimed 661 HP for so-equipped LT4s. This well-traveled V-8 received another set of updates when the CT5-V Blackwing debuted in 2022. The 5-V Blackwing remains in production, and there’s no confusion about the muscle it brings to the table with 668 ponies and 659 lb-ft. The most powerful iteration is currently found in the Cadillac Escalade-V , where the LT4 is really more of an LT4.5, as its 682hp is a result of a larger supercharger borrowed from the next engine up in the LT hierarchy, the LT5.

Engine: LT5

Displacement: 6.2L (Supercharged)

Max Power/Torque: 755/715

Model Years: 2019

Domestic Applications: C7 Corvette ZR1

The ZR1 returned as a one-year send-off for original-recipe front-engine Corvettes and debuted the LT5 along with it, allowing a brief glimpse of what an aluminum pushrod small-block could be with an astounding 755 hp—772 with the optional intake—and 715 lb-ft of torque. The crown sitting atop the LT5 was a massive new 2.65-liter supercharger. Boost went up considerably between the blown Gen-Vs; the LT5 pushed 14 psi to the LT4’s 9.4. Delving into the nitty and the gritty yields other improvements such as the flame-throwing inclusion of direct and port fuel injection, a then-record-sized 95mm throttle body, and an electronically controlled bypass valve sourced from the only of GM’s other engine programs to work with this much torque: the Heavy Duty L5P Duramax turbodiesel!

Engine: LT2

Displacement: 6.2L

Max Power/Torque: 495/470

Model Years: 2020-present

Domestic Applications: 2020-present Corvette Stingray and 2024-present E-Ray

The Gen-V V-8 upped the ante on the LS3 formula for a second time with the LT2. Found behind the driver for the first time in small-block history in the revolutionary 2020 Corvette, the LT2 received some everyday upgrades like a more aggressive cam, but the C8’s engine relocation surgery necessitated several unique modifications, too. Chief among these is the standard dry sump oil system. Previously a hi-po ‘Vette specialty employed to keep oil pressure even during max cornering, the dry-sump oiling in the C8 had the added benefit of allowing GM to move the LT2 lower in the chassis for an optimized center of gravity. Being out of the driver’s forward line of sight also permitted an intake system that is around three inches higher than the LT1’s. With another Z51 performance exhaust option, power was up to 495, once again marking another record for base Corvettes. In 2024, the LT2 was paired with an electrified front axle to create the E-Ray “Corvette of firsts,” with all-wheel drive and hybridization joining the 71-year-old model for the first time. One AC motor partnered with a 1.1 kWh liquid-cooled lithium-ion battery pack to add 160 horses and 125 lb-ft for a total system output of 655 and 595, respectively.

Engine: LT6

Displacement: 5.5L

Max Power/Torque: 670/460

Model Years: 2023-present

Domestic Applications: C8 Corvette Z06

Toffee-nosed detractors of the small-block sang a similar chorus for decades: “It’s a crude and simplistic truck engine, it doesn’t rev high enough, that power-per-liter is weak sauce…” After decades of pushrod success, in 2023, GM went with a both/and strategy like they employed in the C4 Corvette range: a pushrod engine for the base car and the E-Ray, and the screaming DOHC LT6 engine for the C8 Z06. Combined with the ‘Vette’s first-ever flat-plane crankshaft, the LT6 looked like Europe’s greatest hits, but the way it played them had never been seen—or heard—before.

Flat-plane crank V-8s rev faster than their traditional cross-plane counterparts, and in the 5.5-liter LT6, GM set a new record for flat-plane V-8 displacement. This monster, race-proven V-8 also reached a new peak for any American performance car with an 8,600-rpm cutoff, and its 670-horse maximum output beat the previous world record for naturally aspirated V-8 power by putting a 48-equine gap on the famed 6.2-liter V-8 of the Mercedes-Benz SLS AMG Black Series.

Engine: LT7

Displacement: 5.5L (Twin-Turbo)

Max Power/Torque: 1,064/828

Model Years: 2025

Domestic Applications: C8 Corvette ZR1

As if the manic LT6 wasn’t enough, it turns out that GM’s “Gemini Project” was more than just a nod to the Z06 motor’s twin throttle bodies, dual manifolds, and more-or-less balanced pair of inline fours; the engine itself was co-developed alongside a more powerful twin, that itself featured twin turbos. Those snails, famously the largest ever fitted to a production car, have vaulted the LT engine family into hypercar territory for the first time. When outsiders caught Chevrolet benchmarking the ZR1 against the 986-hybrid-horsepower, $600,000 Ferrari SF90, it was easy to think that maybe they were being a bit optimistic, but even the engineers involved were surprised after the LT7’s first dyno test. To start the ZR1’s tire and chassis development, the Corvette team worked with LT5s that were tuned for some hundred extra horsepower, which recently retired Chief Engineer Tadge Juechter said “seemed epic at the time.” But ultimately a ‘roid-raging LT5 and the most powerful Prancing Horse in Ferrari’s stable would both fall short of the finished product in the ZR1. Without having to engage in any hybrid silliness, this boosted take on the 5.5-liter architecture throws down 1,064 HP, or to put it another way, it makes Bugatti Veyron power with half the cylinders and half the turbos for a fraction of the price. And, like its predecessors, it’ll be serviceable at most local authorized Chevrolet dealerships. GM engineer Ed Cole’s personal motto was “kick the hell out of the status quo,” and there might not be a better example of that philosophy than this, ultimate descendant of his fabled small-block V-8 that debuted in 1955.

Epilogue: Where Do We Go from Here?

Over the past 28 years, the LS/LT family proved the viability of “outdated” engine technology. It has grown from a 345-hp icebreaker to a 1,064 (a 308% gain!) showstopper. It is now comfortably the first name in tuning and the go-to for small-batch supercar builders and engine swap aficionados around the world. Where could it possibly go next? As a wise green Jedi once said, “Difficult to see; always in motion is the future.” GM has earmarked nearly $1B for the development of a sixth-generation small-block, but all of the press around this move has revolved around motivating upcoming trucks. We very well could look back at today as the pinnacle of small-block goodness, a time when 495-, 655-, 668-, 670-, 682-, and 1,064-horsepower V-8s are available at your local Cadillac and Chevrolet stores. It’s worth taking a moment to appreciate, and if you have the means, put one in your garage—we may never see anything like this moment in time again.