LS-Series Chevy Small Block

LS-Series Chevy Small Block

The LS-series V8 engine family debuted in 1997. The earliest versions were called Gen III Small-Blocks. Trucks and SUVs got cast iron blocks in trucks while the new C5 Corvette got the all-aluminum LS1. The next year, the LS1 was dropped into the Camaro and Firebird, replacing the previous-generation engine, the Gen II LT1. While both engine were advertised as 5.7 liters, the earlier LT1 had a displacement of 349.8 cubic inches, same as the classic Chevy Small Block, while the new LS1 had a displacement of 346 cubes. Slight differences in bore and stroke made the difference, as the entire engine was re-engineered. However, the classic Chevy Small Block V8 dimension of 4.4-inch bore centers. In 1999, this new Gen III platform spawned a newer, hotter version, the LS6 that came standard in the Corvette Z06 of that year. In 2005, the Gen IV branch of the LS engine family was born. The Gen III now had accommodations for cylinder deactivation cast right into the block and heads, with improved camshaft sensing. It was also designed to be stretched out to until-now-unheard-of displacements (how about a 427 Small Block?!).

The performance versions of the new Gen Iv included the LS2, LS3, the supercharged LS9, and the 7.0-liter LS7. While GM continues to refer to these engines as Gen III or Gen IV, enthusiasts call them LS. On the truck side, the iron-block engines came in 4.8L and 5.3L as well as all-aluminum 6.0L and 6.2L premium engines (GMC and Cadillac). On the performance side, the LS came in 5.3L, 5.7L, 6.0L, 6.2L and 7.0L.


Despite some significant differences between Gen III and Gen IV, the LS-engine family shares a great many common features:
* 4.4-inch bore centers
* 6-bolt cross-bolted main bearing caps
* Center main thrust bearing
* 9.240-inch deck height
* 4-bolt-per-cylinder head bolt pattern
* 0.842-liter bores
* Distributorless, coil-near-plug ignition
The main differences between Gen III and IV are that Gen IVs can take larger bores, the camshaft position sensor was relocated (its at the top-rear on Gen IIIs, and near the front timing cover on Gen IVs), and most Gen IVs had cast-in provisions for GM’s Active Fuel Management cylinder deactivation system.

There is great interchangeability between all LS engines, even between Gen III and IV. Cylinder heads, crankshafts and intake manifolds can all be mixed and matched. However, not every combination will work. An excellent resource for which combinations will work and which will work best, Will Hanzel’s How to Build High-Performance Chevy LS1/LS6 V-8s: Modifying and Tuning Gen III Engines for GM Cars & Pickups (S-A Design) will tell you everything you need.

LS1 5.7-liters, 1997-2004

ABOVE: This 2002 Corvette has an LS1 under the hood.

The LS1 displaced 5.7 liters or 346 cubic inches, and was produced between 1997 and 2004 in the CorvetteCamaroFirebird and GTO. It continued into 2005 in Australia. The LS1 was rated at 350 horsepower and 365 pound-feet of torque and came with aluminum block and heads.

LS2 / L76 / L77 6.0-liters, 2005-present

ABOVE: This LS2 is in a 2007 Corvette. The LS2 was introduced in 2005, displacing 6.0 liters (364 cubic inches), debuting the Gen IV’s unique design features. It was available in the Corvette, the reborn Pontiac GTO, and the retro-styled Chevy SSR convertible pickup. It was also the standard engine in the Pontiac G8 GT sports sedan (engine code L76), and the Chevy Caprice Police Pursuit Vehicle (engine code L77). The LS2 is one of the most versatile members of the LS-series Chevy Small Block family, able to swap heads with an LS1, LS3, LS6 or L92/94.

LS3 / L99 6.2-liters, 2008-2013

LS4 5.3-liters, 2005-2009

Perhaps the most unique application of an LS-series Chevy Small Block is when they stuffed one in the front-wheel-drive 2006-2009 Chevy Impala SS and Pontiac Grand Prix GXP.

LS6 5.7-liters, 2001-2005

The LS6 was introduced in 2001 in the Corvette Z06 and remained in production through 2005. It was also used in the Cadillac CTS-V. While sharing the same 5.7L displacement as the LS1, the LS6 has a strengthened block, improved bay-to-bay crankcase breathing, and unique heads, intake manifold and camshaft. The all-aluminum LS6 was rated at 405 hp at 6000 rpm and 400 lb-ft at 4800 rpm. The name LS6 is not new to Chevy high performance engine lore. In 1970 Chevy introduced the ultimate Big Block, the 454 LS6, rated at 450 horsepower in 1970. Just an interesting footnote.

LS7 7.0-liters, 2005-2013

ABOVE: This LS7 sits in a 2011 Corvette Z06.

The LS7 is only a few years old and its already a legend. The LS7 was the standard engine in the C6 Corvette(2005-2013) Z06 and the 5th-gen Camaro Z/28 (2010-2015). The secret to the LS7’s 505-horsepower was its massive displacement. At 7.0 liters, this LS-series Chevy Small Block matched the 427 cubic inch displacement of the Chevy Big Block that was itself a legend. It’s hard to imagine a basic engine architecture that has survived being stretched from a paltry 265 cubic inches to a whopping 427, but they did it, thanks to the Siamesed-bore cylinder block design of the Gen IV, shared with the LS1, LS2, LS3 and LS6, needed to take the 4.125-inch bore. To support all that potential, competition heads were used, and to withstand the massive 470 pound-feet of torque, lightweight titanium connecting rods and intake valves were used.

LS9 6.2-liters Supercharged, 2005-

The LS9 is the highest-horsepower Chevy Small Block, or any other GM production passenger car engine for that matter, in history with 638 horsepower. The LS9 displaces 6.2 liters and uses a 2.3L Roots-type supercharger with built-in charge cooler, a strengthened block, Rotocast heads and dry-sump lubrication. The LS9 was purpose-built for the C6 Corvette ZR1.

LSA 6.2-liters Supercharged, 2009-present

The LSA is sort of a scaled-back version of the LS9. Both are supercharged and charge-cooled 6.2-liter LS-series Chevy Small Block V8s, similar in design. But the LSA makes 556 to 580 horsepower (depending on application) to the LS9’s 638. The LSA has a smaller Roots-type supercharger, at 1.9 liters, compared to 2.3 liters for the LS9. Because of the reduced loads, the LSA uses hypereutectic pistons compared to the LS9’s forged pistons, and has an 8-bolt flywheel pattern instead of 9-bolts like the LS9. It’s charge-cooler is also set up differently than the LS9, sitting on top of the supercharger. This engine was purpose-built for the 2012-2015 Camaro ZL1 and the 2009-2015 Cadillac CTS-V, even though they had slightly different horsepower ratings. The ZL1 version was rated at 580hp whereas the CTS-V had 556hp.


While the performance branch of the LS-series Chevy Small Block engine family is called LS, the truck engines based on the same platform were dubbed “Vortec”. They generally have cast iron blocks with aluminum heads, and tend to run smaller displacements than their high-performance passenger-car brethren. As a sidenote, GM never offered a Vortec engine in 5.7 liter (350 cubic inch) displacement, however they were produced in the following engine sizes:

* 4.8 liters (293 ci) The smallest of teh LS-series Chevy Small Blocks, using an iron block, aluminum heads and a 3.78″ bore.

* 5.3 liters (327 ci) The classic 327 is back! Uses the same iron block and 3.78″ bore as the 4.8L, but with a longer 3.62″ stroke (almost square). Later versions feature GM’s Active Fuel Management cylinder deactivation system, and 2010-and-newer models ad variable cam timing. Some 5.3L engines come with aluminum blocks.

* 6.0 liters (364 ci) Used primarily in 3/4-ton and 1-ton trucks, the 6.0L could use either a cast iron block (engine code LY6) or an aluminum block (engine code L76), both with aluminum heads. Both featured GM’s Active Fuel Management cylinder-deactivation system and 2010-and-later versions added cam phasing (variable valve timing).

* 6.2 liters (376 ci) Uses aluminum block and heads (about 80 pounds lighter than a cast iron block), with variable valve timing (cam phasing). Referred to by the engine codes L92, L9H or L94, with the L92 being the performance engine optio for the Cadillac Escalade and GMC Yukon Denali.


Chevrolet Performance offers a wide range of crate engines, including every LS-series Chevy Small Block listed here. the LSX-series crate engine is based on the LSX BLowtie Block and uses production based and LSX high-performance parts to deliver top performance.

The Chevrolet Performance Catalog is full of crate engines, blocks, heads, valve trains, trannies, crankshafts, blowers and just about everything else you need to make your GM car or your hotrod fly. The 2018 Chevrolet Performance Catalog is Part Number P/N 19369174. Pick one up at your local GM dealer or go to