2006, the LS7, the ultimate Gen IV engine, was installed in the Corvette Z06 and made quite an impression in the high-performance community. This fire-breathing small-block produced 505 hp and earned the distinction as the most powerful naturally aspirated production small-block Chevy engine ever built. In 2005, the truck engine line changed to the Gen IV platform, adding six new Gen IV blocks. By 2008, the 6.0-liter L76 and the 6.2-liter LS3 joined the Gen IV line. With the popularity of the Gen III and Gen IV engines, General Motors developed specially for the aftermarket the LS364 carbureted Gen IV engine and the LSX bare block for retrofitting and swapping.
To further push the Gen IV performance envelope, General Motors stepped up its game with two new ultra-high-performance engines to stay on top of the late-model horsepower wars: the LSA and the LS9, both based on the LS3 block.
The LSA is a supercharged 6.2 liter that utilizes a 1.9-liter roots-type Eaton supercharger to build 556 brake hp (flywheel) and 551 ft-lbs of torque. The LSA is available in the 2009–up Cadillac CTS-V models as well as the 2012–up ZL1 Camaro.
The LS9 also measures 6.2 liters, but uses a 2.3-liter Eaton Roots blower to generate the 638 bhp and 604 ft-lbs of torque, making it the most powerful GM V-8 ever produced. Just like the LS7, the LS9 features a 10.75-quart dry-sump oiling system. The LS9 is used in the 2009–2013 Corvette ZR1.
In 2013, General Motors released the Gen V platform and adorned it with the LT-series designation. Although not to be confused with Gen II Chevy small-blocks, this engine series will eventually replace the LS-series engine in all platforms. The Gen V shares the look of the III/IV series, but is an all-new engine platform. The LT series’ biggest advancement is the use of direct injection. With this system, fuel is sprayed directly into the combustion chamber at high pressure (2,175 psi for the LT1), increasing fuel economy and overall performance through better fuel atomization. Direct injection also makes cylinder deactivation more efficient, further increasing fuel economy. The 2014 LT1 Corvette can achieve as much as 29 mpg. Other advancements include piston-oiling jets, active fuel management, and continuous VVT.
General Motors wasn’t going to stop there, as it brought out the LT4 in 2015. This is a supercharged version found in the Corvette Z06. The biggest differences from the LT1 to LT4 are lower compression and slightly stronger pistons and rods to handle the additional boost. (Photo Courtesy General Motors)
Chevrolet Performance has released two crate versions of the Gen V: a naturally aspirated 6.2-liter 460-hp LT1, which is the same engine installed in the base-model C7 Corvette, and the supercharged 6.2-liter 650-hp LT4, which comes in the Z06 version of the C7 Corvette. The LT1 for Camaros is rated at 455 hp.
6.2 LT1
Making 460 hp without a supercharger is not easy, and to do so while hitting 29 mpg is even harder, but the LT1 does exactly that. The 4.06-inch bore combined with the 3.62-inch stroke creates an 11.5:1 compression ratio, which makes efficient use of the fuel pumped through the direct-injection nozzles. A forged crank, hypereutectic pistons, and forged powdered-metal rods yield light weight and durability. The heads are conventional aluminum castings that feature lightweight sodium-filled valves.
6.2 LT4
To increase the output of the LT1, General Motors dropped a supercharger onto the 6.2 block to make 650 hp. To make that work long term, changes were made to the rotating assembly. The crank is the same, but the rods were slightly redesigned to increase strength in key areas. The LT4’s pistons are forged and the combustion chamber was opened up, decreasing the compression ratio to a boost-friendly 10.0:1. The rotocast heads are stronger and better at handling higher heat ranges than a typical cast head. The valves are solid titanium and the oiling system is a dry-sump design.
Starting in 2014, all GMC/Chevrolet trucks and full-size SUVs with V-8 gasoline engines come with Gen V engines. Currently three truck versions are available: 4.3 (LT-based V-6), 5.3 V-8, and 6.2 V-8. The V-6 is an LT-series engine, essentially a V-8 with two cylinders cut off. The V-8s are the most common for trucks and SUVs.
5.3-liter L83
This engine features a 3.78 bore with 3.62 stroke. These engines make 355 hp and 383 ft-lbs of torque with gas, while producing 376 hp and 416 ft-lbs of torque with E85.
6.2-liter L86
The L86 is a modified LT1, making 420 hp and 460 ft-lbs of torque. The LT1 and L86 are very similar, down to the compression ratio of 11.5:1.
The purpose of most engine swaps is to increase performance. In almost all cases LS engines meet performance goals. Because the Gen III/IV engine platform represents the largest growing segment of the performance automotive aftermarket, many options are available for increasing the performance of an LS-series engine. Simple bolt-on components include items such as larger throttle bodies or high-flow intakes; serious performance upgrades include items such as high-lift camshafts and large-port cylinder heads.
Although the factory equips its high-performance LS engines with superchargers, a turbocharger is the most effective big-boost upgrade you can install. Driven off exhaust rather than drive belts, a turbo provides “free” horsepower. A 5.3 Vortec engine with a single turbo can make more than 500 hp with no other mods (other than a tune).
With so many options to choose from, Gen III/IV engine swaps have become more and more popular. Once you know where to find the engine that best suits your needs, performing the swap is the next step. The rest of this book deals with how to do this and covers most of the details. Although every car and swap is different, several aspects are common to all.
Swapping an LS-series engine is not the most complicated automotive endeavor. An average swapping project is fairly easy if it is carefully conceived, researched, and planned. The Gen III/IV engine families have footprint similar to the original small-block Chevy. If a traditional small-block Chevy can be swapped into a vehicle, you can certainly install an LS engine, but some minor adjustments such as re-arranging the drive pulleys and other components may be required. The possibilities are truly endless when it comes to LS swaps.
Although most builders are familiar with carburetors and how they work, fuel injection systems, computers, and wiring harness hookups intimidate many swappers. Electronics are a critical component of any swap. In most cases, you must carefully modify wiring harnesses, plugs, and wiring, or purchase the correct aftermarket components for plugging in the particular engine to a specific car. Shops such as Painless Performance provide the products and support to help simplify the wiring harness. Tuning companies such as HP Tuners and EFI Live can reprogram the engine control module (ECM) to adapt it for a swap. In the end, you have a more efficient powerplant with the ability to tune it better and faster.
You can install a carburetor on an LS engine, such as an LS364, and eliminate a big chunk of the electronics. In addition, you can use an aftermarket carbureted intake designed for LS-series engines. LS engines with carburetors are just as powerful and still take advantage of the electronic spark distribution using the one-coil-per-cylinder design. You still need a spark controller, though, because these engines do not have a provision for a traditional distributor, but these control boxes are very easy to wire up.
One of the biggest benefits of the new Gen III/IV engines is their efficiency. They were designed to meet strict Corporate Average Fuel Economy (CAFE) standards for new vehicles. These engines manage
