engine-pedia: EVERY GEN III & GEN IV V8 in the LS FAMILY TREE
Since being launched in 1997 there have been dozens of variants made of the Gen III and Gen IV Chevrolet V8, colloquially known as the “LS”. When it first appeared under the heavily raked bonnet of the all-new fifth-generation Corvette back in ’97, the all-aluminium 5.7-litre V8 was called the “Gen III” as it was the third main redesign of the super-popular Chevy small-block.
Sharing nothing with its iron-based predecessors, the injected, lightweight and very compact pushrod engine ushered in a new era of refinement to V8 GM cars. Its popularity and use across almost the entire GM network over the last 17 years means there is now a mind-boggling number of variants and revisions.
From the original 345hp (260kW) LS1 found in the C5 Corvette through to the 638hp (476kW) LS9, most powerful engine ever offered by GM in a production car, you are faced with a staggering breadth to the family. There are engines for front-, all- and rear-wheel drive, iron and aluminium blocks, cathedral and rectangular ports, many different bore:stroke sizes, dry and wet sump set-ups in a range of front, mid and rear-hump layouts, displacement on demand and variable valve timing technology and more.
The basic measurements for an LS3 is 730mm (28.75in) long, 628mm (24.75in) wide, and 717mm (28.25in) tall, however it is important to note different front drive layouts can change overall width while some truck engines will be 152mm (6in) taller due to their intake manifolds and oil pans. A dressed LS3 is rated to weight 226kg (500lb), while iron LS weigh 50kg more.
As with most popular engine layouts in the US, there are also a swag of blocks and cylinder heads from aftermarket companies. Cataloguing them all would fill a book on their own, so we’ll stick to giving you a rundown of the most popular production LS motors.
3.898” BORE
LS1
The LS1 was all-new for 1997, sharing only con rod bearings with the previous Gen II (LT-series) small block V8s. Chevrolet invested heavily in this new engine, using it as a platform across its whole V8 range and eventually replacing all other V8 engines in the line-up by 2003. The major changes were many, from the 5665cc capacity to the all-aluminium construction (iron blocks came later), to the old five-bolt pentagonal cylinder head stud pattern replaced with a square four-bolt design, six-bolt mains and flat-top pistons (except for later LS9 which uses hypereutectic) for the bottom end and the traditional distributor was replaced by coil-on-plug ignition. The firing order also changed to 1-8-7-2-6-5-4-3, which made it the same as other modern V8s. The then all-new C5 Corvette scored a 345hp (257kW) motor straight up, increasing to 350hp (260kW) while the ‘modern’ F-Body Camaros and Trans-Ams offered between 305-325hp (225-242kW). In Australia, the LS1 replaced the old Iron Lion Holden 304cui V8 in the VT Series II. Originally rated at 295hp (220kW), it grew to 300hp (225kW) in the VX, 308hp (230kW) in the VY and 315hp (235kW) by the VZ, after which it was replaced by the 6L Gen IV V8. HSV tweaked their 5.7 LS1-based V8s from the VT II range onwards, hitting a high of 400hp (300kW) with the Callaway-tuned C4B.
LS6
The LS6 is a high-output version of the LS1 made between 2002-2006. When launched in the C5 Z06 it made 385hp (287kW) modified in 2002 to produce 405hp (302kW) for the Cadillac CTS-V. The LS6 has windows cast into the block between cylinders and features improved main web strength and bay-to-bay breathing, higher flow intake manifold and MAF-sensor, higher lift and longer duration cam, 10.5:1 compression ratio, sodium-filled valves and a revised oil system suited to lateral acceleration. LS6 intake manifolds are also used on all 2001-on LS1/6 engines, including the V8 VX-series-onwards Commodores.
Truck motors: 3.78” bore
LR4
Also known as the Vortec 4800, it is an iron truck motor designed to replace the 305-cube 5000 L30 truck motor. It is the smallest Gen III truck/suv motor and made between 255hp (190kW, 1999-2000), 270-285hp (201-213kW, 2001-on) and then 285hp (213kW) from 2005-2006). They’re found in 1999-2006 Chevy Tahoe/GMC Yukon, Silverado/Sierra and Express/Savana models.
LM4/LM7/L33/L59
The Vortec 5300 engine had several variants over its life, being known as the LM4, LM7, L33 and L59. The stroke is 9mm over the Vortec 4800 and from that point on there are lots of differences. The L33 is also known as the Vortec 5300 HO. It is an aluminium-block variant of the iron LM7 with flat-top pistons from the 4.8L LR4, a higher lift cam, higher compression ratio and LS6 cylinder heads, making 235kW (310hp). The #799 cylinder heads are reportedly the same casting as the LS6 and LS2 #243 heads, minus hollow exhaust valves and high-performance valve springs. The LM4 is another aluminium-block variant of the LM7, making 290hp (216kW) and is not as high-performance as the L33. It was used in the Chevrolet SSR, GMC Envoy and other light-duty models. The L59 is the flex-fuel version of the LM7 found in 1999-2007 Avalanches, Silverados, Sierras, Yukons, Tahoes and Escalades. It makes 270hp (201kW) in 1999, 285hp (213kW) in 2000-2003 and 295hp (220kW) in 2004-2007.
4” BORE
LQ4/LQ9
The Vortec 6000 came in two specifications, with the LQ4 making 300hp to 360hp (220-???kW) and the LQ9 making 345hp (257). The LQ4 is found in GMC Yukons, Hummer H2s, Chevy Suburbans, Chevrolet Silverados, Chevrolet Express and Sierras. The LQ9 is the high-output version of the LQ4, originally designed for Cadillac Escalade models. It has flat-top pistons to increase compression ratio to 10:1. It was also used in Silverado SS and Denali models.
GEN IV
In 2005, after eight years, the Gen III made way for the heavily revised Gen IV series small block, again being unveiled in the new sixth-generation Corvette (C6). Rather than radical re-engineering the platform all over again, Chevrolet evolved the basic architecture to push the displacement as far out as 7011cc (427 cubic-inches), while also including new technology like fly-by-wire throttles (instead of cable), displacement on demand and variable valve timing. The Gen IV has been one of the most horsepower-rich engine line-ups in GM’s history, featuring race-ready powerplants like the dry sumped, 505hp 427-cube LS7 and the King Of The Hill 638hp (476kW) supercharged 6.2L LS9.
3.78” BORE
LY6
The LY6 is a 6.0-litre Gen IV Vortec truck motor which replaced the LQ4, however it boasts variable valve timing. It is fitted to 2007-on Chevy Silverados, GMC Sierras, GMC Yukons and Chevy Suburbans.
LFA/LZ1
Launched in 2008, the LFA is an all-aluminium Vortec V8 and was fitted to GM hybrid GMT900 trucks and SUVs, including Tahoe, Yukon, Escalade, Silverado and Sierra models. The LFA features 10.8:1 compression ratio and makes 332hp (248kW), it was only offered in 2008 and 2009 model years. A heavy revision of the LFA, the all-aluminium LZ1 truck and SUV motor features upgraded fly-by-wire throttle, new oiling system, AFM and variable valve timing while still pumping out 332hp (248kW). It was again offered in 2010-2013 Tahoe, Yukon, Escalade, Silverado and Sierra GMT900 hybrid trucks and SUVs.
LY2/L20
First launched in 2007 GMC and Chevy trucks, the 4.8L Vortec 4800 LY2 replaced the Gen III LR4 and is the smallest member of the Gen IV family. The iron block V8 is also the only Gen IV truck and SUV motor to not feature variable valve timing. It makes between 260-295hp (194-220kW) depending on application. The Vortec 4800 L20 is an iron block Gen IV variant of the LY2, but is equipped with variable valve timing on both intake and exhaust. It does not feature AFM and makes 260-302hp (194-225kW).
LH6/LH8/LH9/LC9
The LH6 is a Gen IV Vortec 5300 5.3L V8 truck/SUV motor with AFM technology and is the aluminium variant of the LY5. It produces 315hp (235kW) and can be found in 2005-2009 TrailBlazers, Envoy Denali, XL and XUVs, Buick Rainiers, Saab 9-7Xs, Silverado 1500s and Sierra 1500s. 300hp (220kW) Vortec 5300 LH8s were fitted to 2008-2010 H3 Hummer SUVs and 2009-2012 Colorado pick-ups, featuring a different sump layout to suit the GMT345 and GMT355 truck engine bays, but do not feature AFM. The Vortec 5300 LC9 is a four-wheel drive fitment, flex-fuel-ready Gen IV making between 315hp (235kW, in pickups) and 320hp (239kW in SUVs). It has been fitted to 2007-onwards Avalanches, Silverados, Suburbans and Sierras. Variable valve timing has been added to the LH6 and LC9 post-2010.
LY5/LMG
The LY5 is an iron block Vortec 5300 engine that replaced the Gen III LM7 engine in 2007. SUV fitments produce 320hp (239kW) while pick-up truck fitment engines make 315-320hp (235-239kW). The LMG is the same as the LY5 except it is the flex-fuel variant. LY5 and LMG engines are found in 2007-onwards Avalanches, Silverados, half-tonne Suburbans, Tahoes, Sierra, Tahoes and Yukons. After 2010 these engines both scored variable valve timing, though the LMG does not feature AFM.
LS4
The LS4 is a 5,328cc (325cui) transverse front-wheel drive fitment Gen IV V8. Construction is all-aluminium, it has AFM and features #243 cylinder heads as found on the LS6, however there are significant changes over rear-drive engines. The bellhousing bolt pattern differs and the LS4 crankshaft is shortened 13mm (3mm at the flywheel and 10mm off the front) compared to a 6.0L. Accessories are driven off a single serpentine belt and the water pump is remote-mounted on an elongated manifold which connects it to coolant passages. The windage trays have also been altered to stave off oil starvation. The 303hp (226kW) engine is found in 2005-2008 Pontiac Grand Prix GXP, 2006-2009 Chevrolet Impala SS, 2006-2007 Chevrolet Monte Carlo SS and the 2008-2009 Buick LaCrosse Super.
4.00” BORE
LS2
Stepping up from the 5.7L, the aluminium LS2 displaces 5967cc (364cui) thanks to a 101.6mm (4.00in) bore and 92mm (3.622in) stroke. It retains the #243 casting cathedral port heads from the LS6 (without lightweight sodium-filled valves) and, in 2005-2007 Corvette-spec, it makes 400hp (300kW) with 2005-2008 E-series HSVs going 12hp better to make 412hp (307kW). Compression was increased over the LS1 (10.25:1) and LS6 (10.5:1) to 10.9:1. Other models which received the LS2 include 2006-2007 Cadillac CTS-V, 2006-2009 Chevrolet Trailblazer SS and 2005-2006 Pontiac GTO and Vauxhall Monaro.
L98/L76/L77
Launched in 2006, the L98 and L76 are 6.0-litre variants of the LS2. The L76 was used in February 2006-on VZ and VE (automatic only) Holden Commodores, Statesmen and Caprices (WL and WM models). L98 versions were fitted to VE Series I (and VZ SS Thunder) Holdens equipped with manual transmissions. While the American market engines scored Displacement On Demand (DOD) technology it was disabled for Aussie motors, though we did score Active Fuel Management (AFM) on cars fitted with 6L80 automatic gearboxes. Removing the DOD and AFM from the L76 changed the camshaft, lifters and other minor fittings in the L98’s top-end. The square-port cylinder heads fitted flow far better than earlier cathedral-port heads however this change in design means intake manifolds and most top-end parts don’t interchange between earlier LS engines and the L98/L76. The introduction of L98 and L76 engines signalled the end of cable throttles for Aussie GM V8s. Holden L76s produce 260kW while the auto Pontiac G8s made 269kW. GM also made a truck variant called the Vortec 6000, based on Holden’s L76, to replace the Gen III LQ9. Found in 2007-2009 Silverados and Sierras it makes 274kW and featured AFM and variable cam phasing. The L77 debuted in the Series II VE Commodores (and Chevy Caprice cop cars), for both automatic and manual transmission choices. The L77 is the flex-fuel variant of the L76 and produces 270kW.
4.06in BORE
In 2007 the LS2 was replaced by a new 4.06in bore family, including the 6.2-litre LS3. They feature variable valve timing and AFM, as well as higher power outputs across the range.
L92/L9H/L94
From 2007 the Cadillac Escalade features the new Vortec 6200 L92, the 6.2L (379cui) all-aluminium V8. Featuring two-stage variable valve timing, it produces 403hp (301kW) and was also found in GMC Sierra Denali and SLT and GMC Yukon, plus export model H2 Hummers, Silverado and Tahoe LTZ. In 2009 the L92 was modified for flex fuel capability and renamed the L9H, while it was again renamed to L94 when AFM technology was added in 2010.
LS3
The 2008 Corvette introduced a new entry level engine that would go on to power most of the factory high-performance GM cars through to today: the LS3. Producing 430hp (321kW), the bore was increased to 4.06in (103mm) over the LS2 to punch the new motor out to 6162cc (376cui), while the camshaft is a more aggressive 0.551-inch (14mm) lift unit and compression is up to 10.7:1. Cylinder heads are rectangle-port castings as found on the L92/L76/L98 with 6mm offset intake rocker arms, 2.165in (55mm) intake valves and 1.59in (40mm) exhaust valves, though the LS3 also scored hollow stem valves that allows it to rev to 6600rpm compared to 6000rpm to the L76. It’s topped off with a higher-flow intake manifold and the same 47lb/hr injectors from the LS7. GM paired this tech to a bi-modals exhaust that gives a 6hp boost to 436hp (325kW). HSV introduced the LS3 in the E1 HSV range, producing 425hp (317kW) before tweaking it up to 436hp (325kW) for the 2009 E2 series and, with the optional bi-modal intake and tube-steel headers, 450hp (340kW) in the Gen-F Clubsport SV. The LS3 has also been fitted to the 2009 Pontiac G8 (nee VE Commodore US export model), the 2008-on Vauxhall VXR8, Camaro SS and Chevrolet SS (nee VF SS-V US export model).
L99
The L99 is a lower-performance variant of the LS3 fitted with AFM and variable valve timing, as found in the Camaro SS. It produces 400hp (300kW), redlines to 6000rpm (not 6600rpm like the LS3) and features different valvetrain to suit the AFM variable displacement.
LSA
The supercharged 6.2L LSA is a lower-performance variant of the LS9 which debuted in the second-generation Cadillac CTS-V (2009). Differences to the LS9 include smaller supercharger (1.9L vs 2.3L), lower compression ratio (9.0:1 vs 9.1:1), smaller intercooler and cast pistons, while some early (Cadillac) LSAs also missed out on the LS9’s piston oil squirters. Originally making 556hp it was bumped up to 580hp for the Camaro ZL1 (2012) and HSV’s Gen-F GTS (2013).
LS9
Based off the LS3, the supercharged LS9 is the most powerful engine ever offered by GM in a regular production model. The 6,162cc (376cui) block is the same as the LS3 as the LS7’s 7.0L (427cui) block was deemed too fragile to withstand the cylinder pressure of forced induction. Equipped with forged 9.1:1 compression ratio pistons and high-strength con rods, the centrepiece is the Eaton four-lobe HTV2300 (2.3L) supercharger. Only offered in the C6 (2009-2013) Corvette ZR1, HSV GTS-R W1, Equus Baas concept car and via GM’s crate motor program, the LS9 produces a mighty 638hp (476kW) and 8190Nm.
4.125” BORE
LS7
In 2006, muscle car fans and Chev-heads lost their collective marbles when the 427 reappeared in the GM Parts catalogue. While it isn’t a big block in the truest sense of the term (it is really a “big small block”) the rest of the specs were mouth-watering. The 7008cc Gen IV LS motor is a hand-built, all-aluminium engine, but very different to other engines in the line-up. The cylinders are a Siamese layout with no water passages between cylinders so Chevy could punch the cubes out while retaining strength. The LS7 runs a wild 4.125” (104.775mm) bore and 4.00” (101.6mm) stroke, while the LS2’s 4.4in (110mm) bore spacing is retained. This required pressed-in cylinder sleeves to retain strength, plus the forged steel crank and bearing caps, forged titanium con rods and hypereutectic pistons all mean the high-revving NA motor will hang together at high-RPM. The LS7 can hit high-RPM thanks to gigantic 2.20in (56mm) Del West titanium intake valves and huge 1.61in (41mm) sodium filled exhaust valves. Power is officially rated at 505hp (377kW), though some claim crate motors will easily spin to over 550hp on engine dynos, while GM testing reputedly saw engines pull to 8000rpm. Along with the track-oriented 2006-2013 C6 Z06 Corvette, the LS7 has been fitted to a wide range of vehicles, including the 2008 HSV W427, Hennessey Venom GT, Camaro Z/28 and a range of helicopters and boats.
GEN III vs GEN IV
Working out if the bargain motor you’ve found is a Gen III or Gen IV is relatively easy. Firstly, Gen IV motors– by and large – all feature electronic throttle bodies, while Gen III engines use cable-operated throttles.
Don’t stress if you’re looking at a bare long motor as there are a couple of generational signatures to these engines that are almost impossible to fudge.
Gen III cam sensors are found at the back of the block, while the Gen IV’s is cast into the front timing cover. The crank sensor is also different between Gen III and IV, even though it is found in the same position on the block. Gen IIIs run a black sensor and 24-tooth trigger wheel, while the later Gen IV crank sensors are grey and 58-tooth.
HEAD IDs
Casting numbers Eng family valve in/ex chamber cc
Cath port
241 LS1 2.00/1.55 67cc
243/799/823 LS1/LS6 2.00/1.55 65cc
706/862/895 LM4/LM7/LR4 1.89/1.55 61cc
853/806/933 LS1 (perimeter) 2.00/1.55 67cc
Rect port
317/035 LQ4/LQ9 2.00/1.55 71cc
373/873 LQ4 2.00/1.55 71cc
364/716/823 L92/LS3 2.165/1.59 68cc
452 LS7 2.20/1.61 70cc
BORE/STROKE
While the external dimensions of the production motors are all largely the same, the bore/stroke changes as capacity climbs. Here are the basic measurements alongside the more popular capacities.
Capacity Bore/stroke (inches)
4807cc/293cu 3.78/3.27
5328cc/325cui 3.78/3.62
5665cc/346cui 3.89/3.62
5967cc/364cui 4.00/3.62
6.2L/376cui 4.065/3.62
7.0L/427cui 4.125/400
What’s in a name?
The “LS” name wasn’t actually an official designation for specific engines – GM always referred to the engines as Generation III (and on) small block V8s. The LS tag grew from Chevrolet’s infamous Regular Production Order (RPO) codes as a way of separating the various specification engines as they popped up.
IRON BLOCKS
It wasn’t long after the aluminium passenger motors were launched that GM reverse engineered smaller-cube iron block engines for their truck and SUV lines. Marketed as heavy duty torque monsters they are worth looking into if you want to build a budget turbo set-up as the iron bottom-ends can take serious punishment. Iron blocks are roughly 100lb heavier than passenger aluminium LS blocks, but can be bored further. Part of the attraction to these motors is larger-capacity car motor internals fit the truck motors. Available in 4.8L and 5.3L sizings you can ID them as opposed to other iron LS blocks thanks to the 4.8/5.3 casting mark on the front of the block. There is no other easy way to ID whether you’re looking at a 4.8 or a 5.3 short of pulling a cylinder head and measuring the stroke. Most people with functioning eyes can identify the “bunch of bananas” style LS car intake manifolds, but the truck and SUV intake manifolds are taller as they feature longer intake runners. They might not look as good but they do help make excellent torque figures.
Iron blocks are roughly 50kg heavier than passenger aluminium LS blocks, but can be bored further. Part of the attraction of these motors is larger-capacity car internals fit the truck motors. While the 6.0-litre truck motors are regarded as the most desirable for big power, GM also made 4.8L and 5.3L capacity engines, which helps with making sure your turbo V8 is able to get past engineering requirements.
But how do you tell your LM7 from your LQ4?
GEN III
3.78in BORE
LR4
Also known as the Vortec 4800, it is an iron truck motor designed to replace the 305-cube 5000 L30. It is the smallest Gen III truck/SUV motor and makes 255hp (190kW) for the circa 1999-2000 edition, 270hp (201kW) from 2001-04, and 285hp (213kW) from 2005-06. It’s found in 1999-2006 Chevy Tahoe/GMC Yukon, Silverado/Sierra and Express/Savana models.
LM4/LM7/L33/L59
The Vortec 5300 engine had several variants over its life, being known as the LM4, LM7, L33 and L59. The stroke is 9mm over the Vortec 4800 and from that point on there are lots of differences. The L33 is also known as the Vortec 5300 HO. It is an aluminium-block variant of the iron LM7 with flat-top pistons from the 4.8L LR4, a higher-lift cam, higher compression ratio and LS6 cylinder heads, making 310hp (235kW). The #799 cylinder heads are reportedly the same casting as the LS6 and LS2 #243 heads, minus hollow exhaust valves and high-performance valve springs. The LM4 is another aluminium-block variant of the LM7, making 290hp (216kW) and is not as high-performance as the L33. It was used in the Chevrolet SSR, GMC Envoy and other light-duty models. The L59 is the flex-fuel version of the LM7 found in 1999-2007 Avalanches, Silverados, Sierras, Yukons, Tahoes and Escalades. It makes 270hp (201kW) in 1999 form, 285hp (213kW) in 2000-03 and 295hp (220kW) in 2004-07.
4in BORE BLOCKS
LQ4/LQ9
The Vortec 6000 came in two specifications, with the LQ4 making 300hp to 360hp (220-268kW) and the LQ9 making 345hp (257kW). The LQ4 is found in GMC Yukons and Sierras, Hummer H2s, and Chevy Suburbans, Silverados and Expresses. The LQ9 is the high-output version of the LQ4, originally designed for Cadillac Escalade models. It has flat-top pistons to increase compression ratio to 10:1. It was also used in the Silverado SS and Denali models. These engines are highly popular given deep-breathing LS3-style heads can be fitted for bulk turbocharged power.
Featuring 9.4:1 compression ratio, LQ4s are a Gen III motor and run a 24-tooth reluctor wheel. In 1999-2000, LQ4s came with #373 or #873 heads that had 71cc chambers, cathedral ports and 200cc intake runners with oval exhaust ports. From 2001-07 LQ4s were fitted with the cathedral-port, 210cc intake, #317 or #035 heads that had D-shaped exhaust ports
GEN IV
In 2005, after eight years, the Gen III made way for the heavily revised Gen IV-series small-block. Rather than radically re-engineering the platform, Chevrolet evolved the basic architecture to push the displacement as far out as 7011cc (427 cubic-inches), while also including new technology like fly-by-wire throttles, displacement on demand and variable valve timing.
3.78in BORE BLOCKS
LY6
The LY6 is a 6.0-litre Gen IV Vortec truck motor which replaced the LQ4, however, it boasts variable valve timing. It is fitted to 2007-onwards Chevy Silverados and Suburbans, and GMC Sierras and Yukons. Due to its smaller bore size it cannot use the high-performance LS3 rectangle-port heads.
LFA/LZ1
Launched in 2008, the LFA is an all-aluminium Vortec V8 and was fitted to GM hybrid GMT900 trucks and SUVs, including Tahoe, Yukon, Escalade, Silverado and Sierra models. The LFA features 10.8:1 compression and makes 332hp (248kW). It was only offered in 2008 and 2009 models. A heavy revision of the LFA, the all-aluminium LZ1 truck and SUV motor, features upgraded fly-by-wire throttle, new oiling system, AFM and variable valve timing while still pumping out 332hp (248kW). It was again offered in 2010-13 Tahoe, Yukon, Escalade, Silverado and Sierra GMT900 hybrid trucks and SUVs.
LY2/L20
First launched in 2007 in GMC and Chevy trucks, the 4.8L Vortec 4800 LY2 replaced the Gen III LR4 and is the smallest member of the Gen IV family. The iron-block V8 is also the only Gen IV truck and SUV motor not to feature variable valve timing. It makes between 260-295hp (194-220kW) depending on application. The Vortec 4800 L20 is an iron-block Gen IV variant of the LY2, but is equipped with variable valve timing on both intake and exhaust. It does not feature AFM and makes 260-302hp (194-225kW).
LH6/LH8/LH9/LC9
The LH6 is a Gen IV Vortec 5300 5.3L V8 truck/SUV motor with AFM technology and is the aluminium variant of the LY5. It produces 315hp (235kW) and can be found in 2005-09 TrailBlazers, Envoy Denali, XL and XUVs, Buick Rainiers, Saab 9-7Xs, Silverado 1500s and Sierra 1500s. Vortec 5300 LH8s making 300hp (220kW) were fitted to 2008-10 Hummer H3 SUVs and 2009-12 Colorado pick-ups, featuring a different sump layout to suit the GMT345 and GMT355 truck engine bays, but without AFM. The Vortec 5300 LC9 is a four-wheel drive fitment, flex-fuel-ready Gen IV making between 315hp (235kW, in pick-ups) and 320hp (239kW in SUVs). It has been fitted to 2007-onwards Avalanches, Silverados, Suburbans and Sierras. Variable valve timing has been added to the LH6 and LC9 post-2010.
LY5/LMG
The LY5 is an iron-block Vortec 5300 engine that replaced the Gen III LM7 engine in 2007. SUV fitments produce 320hp (239kW) while pick-up truck fitment engines make 315-320hp (235-239kW). The LMG is the same as the LY5 except it is the flex-fuel variant. LY5 and LMG engines are found in 2007-onwards Avalanches, Silverados, half-tonne Suburbans, Tahoes, Sierras and Yukons. After 2010 these engines both scored variable valve timing, though the LMG does not feature AFM.
4.06in BORE BLOCK
L92/L9H/L94
From 2007 the Cadillac Escalade featured the new Vortec 6200 L92, the 6.2L all-aluminium V8. Featuring two-stage variable valve timing, it produces 403hp (301kW) and was also found in GMC Sierra Denali and SLT and GMC Yukon, plus export model H2 Hummers, Silverado and Tahoe LTZ. In 2009 the L92 was modified for flex-fuel capability and renamed the L9H, while it was again renamed to L94 when AFM technology was added in 2010.
PICK A WINNER
Working out if the bargain motor you’ve found is a Gen III or Gen IV is relatively easy. To start with, Gen IV motors – by and large – all feature electronic throttlebodies, while Gen III engines use cable-operated throttles.
Don’t stress if you’re looking at a bare long motor as there are a couple of generational signatures to these engines that are almost impossible to fudge.
Gen III cam sensors are found at the back of the block, while the Gen IV’s is cast into the front timing cover. The crank sensor is also different between Gen III and IV, even though it is found in the same position on the block. Gen IIIs run a black sensor and 24-tooth trigger wheel, while the later Gen IV crank sensors are grey and 58-tooth.