Since its triumphant debut under the hood of the new-for-‘97 C5 Corvette, the LS-series of Chevrolet small-block or (medium-displacement) engines have built a reputation for seemingly limitless performance in a small but potent package. As the years and development progressed, GM’s finest high-performance offerings, reading like a list of Hall of Fame ball-players, were fitted with more powerful and efficient versions, allowing the LS to claim the throne as the dominant powerplant for its generation and beyond. After two decades of regular production, with unrivaled aftermarket support and still-growing crate motor demand, we at LSX Magazine celebrate our namesake in telling the story of the LS-motors in all their iterations and glory.
CHAPTER ONE: GEN III LS1
Taking four decades of knowledge and experience into account, the powers that be at GM/Chevrolet Powertrain sought to deliver the ultimate evolution of the small-block V8 motor. The new engine would encompass proven methods of engine production and introduce new ideas that carry on 20 years later, still providing the majority’s choice for making real power in a myriad of applications.
When it first appeared between the C5’s fenders–the single in-block camshaft LS1 surprised many and caused more than a few chuckles among the high-performance competition. But almost as soon as America’s fresh, new sports car started to flaunt it’s 345 hp/350 lb-ft of naturally breathing grunt to the rest of the planet, it was obvious that “world-class” was a term that applied to any discussion about the LS and needless to say, the chuckles abruptly ended.
Block to heads, the new engine was all-aluminum and modular construction with a coiled snake-like composite intake sitting on top, meaning lighter, better and almost forever. The longevity of a well maintained twenty-year-old LS1 is common lore among tales of late-model performance machines. It seems the older they get, the better they perform.
In 1998, GM’s F-Body duo, the Camaro and Firebird, joined the bandwagon receiving fresh fascias and their own LS1s. Seated within their long sloped pony car mugs, 305 hp/335 lb-ft were regular Z/28, Formula and Trans Am numbers, while the freer-breathing, bulge-hooded SS and Ram Air WS6 cars got 320 horses and 345 lb-ft of tush-tucking torque. The same lightweight internals – like powder metal connecting rods with hypereutectic (cast aluminum alloy with high silicon content) pistons, a hydraulic roller camshaft and high-ratio rocker arms – propelled GM’s corporate cousins to a new level of pony car prominence and more than a gallops-stride ahead of their crossed-town rival’s blue oval pony. Even Cobra venom had little effect, until 2003, when Ford’s snake-branded ‘Stang got a blower as an equalizer. By 2002, and with the sorrowful demise of the F-body SS/WS6 Ram Air, LS1-cars churned-out 325 hp/350 lb-ft, figures widely rumored to be underrated.
HAULIN LS: TRUCK/SUV GEN III LS VARIANTS
Often touted as GM’s icing on the cake, or where they make the real profits, in 1999, many of the General’s trucks and SUVs received LS motors. Referred to as the Vortec series, light trucks like the Chevy Silverado and GMC Sierra got either the iron block/aluminum headed 4.8L (LR4) and 5.3L (LM7), or the big dog all-iron-block/heads 6.0L (LQ4). Ranging from 255 hp/285 lb-ft to 300 hp/355 lb-ft, with those numbers rising steadily over the model years. GM’s cast iron LS iterations not only made for some pretty powerful trucks, but shared the same modular architecture with their aluminum brethren, making for easy parts transfer between car and truck applications. Ironically enough, unlike their car cousins, no 5.7L LS truck/SUV variant was ever factory fitted.
In 2001, the 6.0L LQ4 was updated and was offered for the first time with aluminum heads. For 2002, to up the ante even further, a new 6.0-liter mill with higher compression, dubbed the LQ9, made 345 hp/385 lb-ft in the big “playa” Caddy and soon became the hot choice for big-power build-ups. The only difference between the LQ4 and LQ9 being slightly beefier connecting rods and flat-top pistons, as opposed to the LQ4’s dished set.
A flex-fuel version of the LM7, named the L59, was debuted in 2002 as well–though not many differences separated it from the LM7. Produced through 2007, the L59 made the same power as the LM7 throughout its production.
Also included in the truck family, the 2003-’04 Chevy Super Sport Roadster (SSR) retro-styled pick up, first got LS-power in the form of an updated and 100-lbs lighter, aluminum-block 5.3L (LM4) good for 300-ponies, which was shared with the Trailblazer, GMC Envoy, Isuzu Ascender, and Buick Rainier. The 2005-’06 SSRs and later Trailblazer SS received the upcoming Gen IV LS2.
RETURN OF THE GOAT: 2004 GTO
As Pontiac prepared to reintroduce its father of the musclecar, the first part of the recipe agreed-on by then Vice Chairman of GM Global Product Development Bob Lutz and the Holden/Pontiac design team, was that the new Goat would definitely sport LS power. The CV8-Monaro-based GT car would get the C5’s LS1 of the day, with the same 5.7L and 10.1:1 compression, but no longer down-graded as on the now deceased F-bodies. The new “Great One” pumped out full ‘Vette-power with 350 horses, though it produced 10 less lb-ft at 365. But even with slightly less torque, it was capable of ripping mid-4-second 0-60-mph launches. If the neo GTO wasn’t what the purists wanted looks wise, they, and virtually no one, could argue with the high-performance marriage made in heaven between the LS1 and the Aussie-built coupe.
HOT-RODDED LS1: LS6
Five years into the LS1’s reign of internal combustion supremacy, GM/Chevy dipped into its bag of tricks and iconic nomenclature, unleashing the 2001 Z06 Corvette with an exclusive hopped-up version of the LS1–designated the LS6.
Basically a hot rodded or “Hyde” version of a mild-mannered Dr. Jekyll LS1, with the same 5.7L/346-cubes–the LS6’s weoponizing begins with a stronger cast block and larger bulkhead windows for increased bay-to-bay crankcase ventilation at the Z06’s higher RPM range. The Z06 also got better-flowing 243 casting heads, which featured upgraded valves with hollow intake stems and sodium-filled units on the exhaust side for better heat dissipation, a larger-volume intake plenum, a larger MAF, a revised bump stick, and upgraded fuel shooters. The smaller combustion chambers equated to a higher 10.5:1 compression ratio, 385-rip-roaring horses and lb-ft of torque and arguably, one of the best performing Corvettes to date.
Never resting on its [GM/Chevy] laurels, and eager to further demonstrate the seemingly endless performance potential of the LS, more power and improvements lavished the LS6 for 2002. The up-gunning included, a higher lift camshaft, more efficient cat-converters, a bigger air cleaner housing, and a reprogrammed and screenless MAF sensor. The new numbers were 405 hp/400 lb-ft and that’s naturally aspirated ladies and gentlemen. The Fixed Roof Coupe (FRC) 2001-‘04 C5 LS6-powered Z06 still trounces higher horsepower modern machines on road courses, present day.
CLASS MEETS MUSCLE: 2004 CADILLAC CTS-V
As GM’s luxury division was undergoing a change of its spots, and transforming from boring to ballsy, the first of the new high-performance-oriented V-series cars, the CTS-V, was fitted with none other than the Z06 Corvette’s no longer exclusive LS6 mill. Making a tad less power/torque at 400 hp/395 lb-ft because of different exhaust manifolds and tuning, the LS-powered Caddy never the less changed forever the mantra and reputation of GM’s flagship division and created a connection to its Corvette cousin that continues to this day–more on that to come.
For the ‘05 model year, the first of the Gen IV LS-series engines appeared. This new batch was manufactured with Siamese-bore cylinder blocks for extra strength/increased bore capacity and incorporated in-block casting provisions (lifter bleed-down towers) for higher tech functions such as Active Fuel Management (AFM) for more efficient cruising on half cylinder power. Gen IVs also have relocated camshaft position sensors, from the top-rear on Gen IIIs to the front of the timing cover. This new GM technology allowed their new more powerful motors to deliver government-mandated fuel mileage smiles and most importantly, stay in the good graces of their performance-loving customers. With that, the LS2 now replaced the venerable and already fabled Gen III 5.7L LS1/LS6 as standard issue.
It first came packaged in the new-for-’05 C6 Corvette and the second-year GTO and then finished the production runs of the Trailblazer SS and first-Gen CTS-V Caddy. Still utilizing the cathedral-ported (243-cast) LS6 heads, but with solid intake and non-sodium-filled exhaust valves–the LS2 was a 6.0L/364-cid-mill, with 10.9:1 compression, making 400 hp/400 lb-ft. None of the lucky LS2 recipients featured AFM, however, but the soon to be ’08/’09 Holden Commodore-based Pontiac G8 GT did, via the L76 variant. The L76 was basically an LS2 with 6.2L/L92 aluminum Vortec truck heads featuring the better-flowing rectangular ports and an L76/LS3 intake. The G8 GT, Caprice PPV and most GM trucks from ‘07-’09, along with some 6L80-E automatic-shifted and VVT-equipped ‘09 Holden vehicles, received the L76–just another nod to the interchangeability of components among the LS family.
GEN IV VORTEC
Trucks and SUVs benefited from the new technology as well, as both 6.0L iron block/aluminum heads (LY6) or aluminum block/heads (L76) engines were AFM, and Variable Valve Timing (VVT)-capable. The larger displacement 6.2L L92 all-aluminum engine also includes all the performance and fuel-saving bells and whistles, primarily used in the General’s big trucks/SUVs like the Caddy Escalade and Yukon Denali, among others.
There is a myriad of Gen IV LS-designated truck engines, offering VVT, AFM and Flex Fuel capabilities that came online through the model years, but for the purposes of this article, we focused on the most prolific variants and those most widely compatible with performance car LS set-ups.
THIRD TIMES A REAL CHARM: LS3
Like consecutive great Beatles albums back in the day, the LS hits just kept coming and for 2008 the LS3 debuted at the top of the charts and once again, in America’s sports car. The LS3 was the evolution of everything right about its LS1/LS2 predecessors, with upgrades where needed to produce the most powerful base Vette engine ever (430 hp) to that point. The LS3 served as the C6 Vette’s standard engine until the end of its run in 2013.
With a very similar block to the reigning LS2, the LS3 was reinforced to support its bored-out 6.2L/376 cubes. Internally, the LS3 employed larger/refined pistons, larger valves with hollow intake stems for increased performance and a slightly higher-lift bumpstick.
Like all LS motors, the crux of the power is in the heads and the LS3 came capped by some of the best ever designed. These rectangular port pieces with their larger off-set combustion chambers, allow for increased flow characteristics for the bored-out displacement of 6.2L, at a slightly less than LS2 compression ratio of 10.7:1. The L92 heads are an almost identical design, the only difference being that they utilize a solid intake valve.
Both head designs are actually very similar to those on the LS7 Z06, and by extension the C5R, minus the extensive CNC-machining for the big 427-cid mill. The L92/LS3 design was even good enough to make the cut for the supercharged LS9/LSA variants–though the LS9/LSA heads have a slight “blend bump” cast into the intake ports and the LS9 casting are designed for use with 12mm head bolts instead of the standard 11mm. Both the LSA and LS9 are rotocast making for a stronger design and the LS9 head uses titanium intake valves.
The LS3 also employs a larger volume intake plenum for increased inhalation and new insulated engine covers, to help shush the big motors chatty valvetrain.
A NEW CHEVY PONY: 2010 CAMARO
After an eight-year hiatus, the Camaro returned for the 2010 model year and was fitted with the LS3 kicking-out 426-ponies. Like all Gen IV LS motors, the LS3 comes (AFM) cylinder deactivation-ready (though not equipped) while the automatic-shifted SS Camaros got the gas-saving tech in the form of the (L99) variant and 26-less stallions. The LS3 remained standard issue SS Camaro weaponry until the end of fifth-gen production.
THE LAST GREAT PONTIAC: 2009 G8 GXP
Recorded as one of the great crimes in recent history, 2009 would be the last full year of production for GM’s famed “Excitement” division. As a fitting farewell, the G8 GXP high-performance sedan was equipped with the LS3 in both automatic and 6-speed manual trans guise, making 415 hp/415 lb-ft. Only 1,829 of the final flagships were produced, making them one of the rarest of factory-fitted LS3-powered machines.
AUSSIE CONNECTION 3.0: CHEVY SS 2014-’17
After fitting the LS1/LS2 into the ’04-’06 Pontiac GTO and the L76/LS3 into the ’08-’09 G8 GT/GXP, GM once again sought LS-power from “down under” in the form of the Chevy SS. Holden Commodore-based like the G8, the muscular SS sedan, sports the LS3 with the same 415 hp/415 lb-ft as the GXP, in auto or stick shift and with Magnetic-ride shocks. Chevy SS and all Holden production ceases after the 2017 model year, making them the last of GM’s factory-fitted LS-powered machines.
Adding versatility to the LS repertoire, 2005-’09 GM W-bodies, including the Chevrolet Impala/Monte Carlo SS, Pontiac Grand Prix GXP and Buick Lacrosse Super, are fitted with the LS4. An all-aluminum version of the 5.3L Vortec motor, with LS6-style LS2 heads–this unique iteration is transversely-mounted for front-wheel drive applications and has a 13mm shorter crankshaft, transmission-mounted starter and a low-profile, single-belt accessory system/water pump for its special fitment. The LS4 makes 303 hp/323 lb-ft respectively and was one of the first Gen IV LS variants to feature AFM.
RACE BRED: LS7
Rewinding a bit, back to 1999, the C5-R Corvette began what would be one of the most dominant factory-backed runs in racing history. When it was all said and done, the Corvette Racing team had amassed 45 of 66 event wins, with 31 1-2 finishes, including three 24 Hours of Le Mans GTS-class championships and five-straight ALMS championships.
The engine that propelled the victorious ‘Vette, while based on the Gen III LS architecture, used a unique engine block and head design specifically built for the demands of an endurance engine. Improvements to the head and block design would would later be incorporated to the LS7 engine. The C5-R’s mill also displaced 7.0L, with a 12.5:1 compression ratio, and made 600 horses, enabling the C5-R able to achieve 200 mph in the blink of an eye.
Fast-forward to 2005 and the C6.R was poised to take over where its legendary predecessor left off. Along with a new and improved chassis and shell, the C6.R would once again wield the immense power of one of the most potent naturally-aspirated engines in automotive history and the largest displacement production LS ever–the LS7. This once again lead to further improvement on the LS7’s design before its release to the public.
The following year, civilian ‘Vette-buyers got their own race-ready C6 in the form of the new Z06. Fitted with a tad-detuned version of the C6.R’s motor with a smaller 4.125-inch bore size, the Z06’s streetable and hand-assembled 7.0L/427-cid LS7 featured pressed-in steel cylinder liners to sure up the larger bores within a completely machine-honed block. Super strong and lightweight internals mimic the race motor, like a forged steel crankshaft, titanium connecting rods with anodized polymer-coated pistons and forged 6-bolt main caps. The LS7 Z06 was also the first production ‘Vette to feature dry sump oiling.
Top end components were key in delivering the most powerful small-block motor ever produced and the LS7 features its own unique cylinder heads stuffed with titanium intake valves and meticulously CNC ported – just like on the C5-R – for extremely high-flow breathing. However, the LS7 heads differed slightly from the C5-R pieces as the racing head used an aggressive 11-degree valve angle. The LS7, on the other hand, utilizes a 12-degree valve angle, which is still an improvement over the LS engine’s standard 15-degree valve tilt. The ports on the LS7’s intake plenum also match the heads, further aiding air flow and making them one of the highest flowing heads GM has ever produced.
Numbers for the LS7 are a conservatively-rated 505 hp/470 lb-ft, along with being one the first manually shifted, regular production pushrod engines to have a 7,000+rpm redline. Further adding to the LS7’s exclusivity, for 2014/’15 the Z/28 returned to Chevy’s paddock of performance, now graced with its big brother’s race-derived heart, making for the most serious, naturally breathing, track-ready Camaro to that point. That said, as legendary as the LS-series of engines truly are, to many, the mighty LS7 definitely stands as King Arthur.
Even with the LS7 perched high at the helm of the LS hierarchy, in 2009, a new iteration arrived, one that would not only take the crown, but conquer the world. The LS9 was the culmination and apex of all LS variants preceding it, maximized by forced-induction. Conceived and built exclusively for the king of Corvettes, the ZR1, the LS9’s ascension to the crown was absolute.
Based on the LS3’s 6.2L/376-cid dimensions, its prowess doesn’t stem from just plopping on a blower, rather, it starts with a 20 percent stronger block cast from 319-T7 aluminum and, harkening back to the LS6, includes enlarged bulkhead windows for better bay-to-bay breathing and to lessen the pumping pressure on the piston’s downward stroke.
Hand-built and deck-honed at GM’s Wixom, Michigan Engine plant alongside its big-bored brethren, the LS7, the LS9 shares race-proven internals like a forged micro-alloy steel crankshaft, titanium connecting rods and intake valves, but adds stronger and lighter forged-aluminum pistons with oil-spray cooling to help reduce the temps and friction produced by the ultra high-performance blown motor.
The LS9’s cylinder heads are of the L92/LS3 design and include the aforementioned titanium intake valves, but are formed via Roto-casting, which produces an even stronger and structurally sound piece for extended life under supercharged usage.
The LS9 employs a specific refined, low-overlap camshaft to ensure comfortable low-rev function and direct-response all through the powerband along with a unique Dual-Pressure/Center-feed fuel system to ensure proper go-go juice pressure distribution in all driving situations.
Already a serious-business motor, the LS9’s claim to fame and ultimate power comes from a state-of-the-art, briefcase size, Eaton R2300 2.3L twin high-helix (twist) four-lobe rotor, positive-displacement Roots-type supercharger throned atop the LS9’s valley cover. Integrated within the blower case, dual air-to-liquid intercooling “bricks”, living right above the rotors, drastically lowering the temperature of the charged air entering the combustion chambers for optimum supercharger performance and prolonged life. The whole song and dance fits perfectly in place under the super C6’s hood and shines like an automotive “Picasso” through the ZR1’s exclusive polycarbonate window.
The fruits of this LS-lavishing were 638 hp/604 lb-ft with 10.5 psi of boost. Performance for the manually-shifted-only ZR1 was quite astounding for its day, and any day for that matter, with 3.3-second First-gear-only 0-60 sprints, 11-second 1/4-mile passes and a Corvette/GM first, 200+mph supercar top speed all day long and twice on Sundays.
The stats for the blown beast speak for themselves and stood as the most powerful GM engine/car ever produced from 2009-until the advent of the supercharged LT4 in the 2015 Z06. Regardless of the new LT-powered C7’s present standing, to many ‘Vette aficionados, the LS9-ZR1 still holds the crown and is credited with teaching the LT4-C7 Z06 everything it knows.
Following closely in its corporate cousin’s burnt rubber, the second-generation V-series Caddy’s were blessed with a non-hand-built and slightly milder version of the ZR1’s LS9, designated as the LSA. From 2009-’15, CTS-V sedans/coupes and yes, wagons, were fitted with the supercharged engine making 556 hp/551 lb-ft in either six-speed stick or automatic guise.
Differences between the LSA and its blown big brother were few but significant and include, a smaller 1.9L Eaton supercharger, making a little less max boost at 9 psi, with a revised single-brick intercooler, forged powder-metal connecting rods instead of titanium and cast-iron exhaust manifolds doing the job of the LS9’s stainless steel pipes. A considerably less aggressive camshaft was also fitted to the LSA. Like the LS3/LS7/LS9 before it, the LSA employs an advanced ignition system that used a 58X reluctor wheel to send pulses to the ECM for optimal ignition timing, performance and economy–earlier LS motors used a 24X unit. Until the 2016 LT4 CTS-V arrived, the LSA-powered V-cars were the most powerful, best performing Cadillac’s ever built and still stand as a match for just about anything on the road today.
NO COPO NEEDED: 2012-’15 ZL1
Back in 1969, if your name wasn’t Fred Gibb or Don Yenko and you weren’t aware of the enigma that was the Central Office Production Order (COPO), you probably weren’t getting your grubby hands on a ZL1 427-cid-powered Camaro, at least not without some connections and serious late-‘60s moola.
That said GM/Chevy reintroduced the ZL1 Camaro for 2012, now available to all, from their local dealers and powered by the same supercharged LSA engine found in its luxury-laden Caddy cousin, the CTS-V. The Camaro however, benefits from a revised supercharger lid allowing better air flow, revised intercooler bricks, air-intake/lower restriction filter for improved flow through it’s blower, a dual-mode exhaust borrowed from the ‘Vette and hydroformed T-309 stainless steel exhaust manifolds, a la LS9, to squeeze-out 580 hp/556 lb-ft. Even with the 650-horse LT4 taking the duty in 2016, the fifth-gen ZL1 will stay on that short and esteemed list of the most powerful Camaros ever built.
To many late model GM enthusiasts, gearheads and our own esteemed staff here at “LSX” Magazine, the term or prefix LSX, refers to any and all LS-series engines, their related components and the vehicles blessed with them.
In all accuracy and technicality, however, and risking an e-mail scolding from my editor, LSX denotes a particular Chevrolet Performance series of LS blocks, conceived and developed from C5-R, C6.R/LS7 racing experience and purposefully manufactured for all-out performance in racing or hot-rodded applications.
The Chevrolet Performance LSX “Bowtie Blocks” are based on the same modular design, production-based Gen IV LS motors, but feature a cast iron, Siamese-bore cylinder block with six-bolt heads for unrivaled strength, able to support naturally-aspirated, forced-induced or even nitrous-assisted build-ups of over 2,000 hp. LSX blocks come with a priority oiling system and can be bored from 4.000 to 4.250-inches (6.0L-7.4L), in standard deck form, or up to 500cid with a tall deck and the appropriate crankshaft. LSX engines can come in short- or long-block configurations, full factory crate setups and can be carbureted or EFI-controlled, while accepting the full gambit of LS components to suit the vehicle intended and the needs, desires and goals of its builder. Similar LSX-style blocks are available from aftermarket manufacturers and can be built-up using OEM/aftermarket LS components.
ODE TO PONTIAC:
Being a full-on Pontiac fanatic, owner and writer of all things “Poncho,” especially the “Arrowhead’s” late model LS-powered offerings, your author thought it appropriate and necessary to mention the apparent similarity of the LS-series to the iconic all-block motors from Pontiac’s engine-building heyday.
Although there are differences between the Gen III/IV LS blocks, the same concept, apparent in the 1955-1981 Pontiac-made blocks, seems clear. Where the Excitement division’s blue-painted mills could come in 287-455-cid bore displacements, they started life from basically the same iron chunk, then added different heads, intakes, carbs, cams and so-on over the decades.
Similarly, the LS1/LS6, LS2/L76 LS3/L99, LS9/LSA, all cast-iron and aluminum Vortec truck motors and even the LS7 and non-production LSX engines can be re-sleeved, bored/stroked and intermingled with their LS brethren through a basic like-design and complimentary high-performance and high quality components.
If you don’t believe me, please refer to these source materials used in the research/writing of this article, they were written by real experts and are invaluable literature for all LS history/information and parts compatibility.
Chevy LS1/LS6 Performance, by Christopher P. Endres
How to Build and Modify GM LS-Series Engines, by Joseph Potak
How to Build High-Performance Chevy LS1/LS6 V-8s, by Will Handzel
Corvette Black Book 1953-2016, by Mike Antonick
Trying to encompass the last twenty years of LS power and production into a few thousand words isn’t easy, with such impact and significance to the automotive world, there seems to always be something more to say.
It’s not just the fact that the LS had huge cylinders to fill, following a historic and iconic lineage of Chevrolet engines, or that the vehicle that got first dibs, was unmistakably titled as America’s sports car.
It’s not only the fact that Chevrolet sought to stay with a simple operating design of the single in-block camshaft and pushrod configuration, ceaselessly modernizing and maximizing it at every chance.
It’s not just the fact that the LS-series of engines provided advanced emissions and fuel saving technologies while making more and more power from subsequent variants.
It’s not just that LS engines can be found in some of the most advanced and powerful cars/trucks that GM and its subsidiaries have ever produced–cars that changed the face of GM, challenging and surpassing the world’s best competition on the street and dominating motorsports like no series of powerplants before it.
And it’s not just the fact that the Gen III/IV LS motors are directly and solely responsible for the new Gen V LT-line of GM engines, that feature even more astounding output and higher-technology. No, it’s all of these factors and probably a few I forgot to mention and will regret not listing later.
Since being unleashed twenty years ago, LS engines have become synonymous with the pinnacle of late-model GM high-performance. Like the old adage says: “If you want to go fast–put a Chevy in it.” The LS-series of engines has built a reputation that continually builds upon itself. Whether it be in the array of formidable production vehicles graced with factory fitment or the endless, resto-projects, hot rods, customs, racing applications and even non-GM and non-American car/truck builds, the General’s/Chevrolet’s, 1997-‘17 medium-displacement engines designated “LS” have most definitely and deservedly earned their Legend Status.