Development for the Gen III engine began after the short-lived LT1/LT4 (1992–1997) engine failed to meet GM’s performance expectations. General Motors essentially started from square one and created the new Gen III V-8 engine, which shared very little with the original small-block Chevy LT1/LT4 plat-form that it replaced. A phenomenal high-performance engine, the Gen III LS1 showcased modern engine technology while retaining the traditional pushrod valvetrain. The engine first appeared as the flagship engine in the 1997 Corvette, generating a groundswell of enthusiast interest, and a whole series of high-performance Gen III/Gen IV engines followed it.
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Although many consider these “LS” engines, the official nomenclature is Gen III and Gen IV. These remarkable engines produced classleading performance and fuel efficiency. As a result, street rodders, muscle car enthusiasts, and even sports car aficionados recognized the potential of the potent, compact V-8 engines and sought out Gen III/IV engines for swapping into a wide range of vehicles. The factory small-block engines pushed out 350 hp at the low end of the scale and reached more than 500 hp at the top end of the spectrum. It seemed the horsepower wars from the late 1960s were back again. In addition, Gen III/IV engines transformed GM’s performance business, now called Chevrolet Performance, and released a full complement of high-performance parts for the powerhouse engine.
The desire to swap these engines into other vehicles is at an all-time high. Finding an LS engine for your project can be as simple as strolling through the local wrecking yard, visiting a website, or making a single phone call to your local dealer. Furthermore, you have quite a few versions of these venerable engines to choose from.
Gen III: A Revolution in V-8 Performance
All-aluminum or cast-iron blocks built from 1997 through 2004 are basically the same. However, there are some minor differences, including an important internal difference. The outside diameter (OD) of the camshaft bore was changed in 2004. Although the cam itself remained the same, only the bearing OD changed, and as such it required a different set of cam bearings.
General Motors utilized the Gen III platform for the full range of GM trucks as well. With two years of experience under its belt, General Motors replaced the aging Gen I 305 and 350 small-block truck engine platform with Gen III engines. The new truck and SUV powertrain was offered in three displacements: 4.8-, 5.3-, and 6.0-liter. These V-8 engines were installed in every GM truck and SUV from 1999 to 2007. The 4.8- and 5.3-liter engines share aluminum cylinder head design; the larger 6.0-liter engines have their own aluminum head design. The heads do, however, swap across all blocks. The Vortec truck engines have proven to be a very popular swap candidate due to sheer volume and low cost.
Gen IV: Improving the Legend
In 2005, when the Gen IV platform began replacing the popular Gen III, the evolution in pushrod engine technology took another step forward. Based on Gen III architecture, these new engines took advantage of displacement-on-demand (DoD) technology, which General Motors called Active Fuel Management (AFM). AFM allows the engine to alternately fire the pistons between all eight or as few as four pistons, saving fuel and reducing emissions. This technology has been offered on the Gen IV platform; this engine series was even designed to accept variable valve timing (VVT) and three valves per cylinder. The first Gen IVs were the LS2 and the front-wheel-drive V-8 LS4.
However, the Gen III production engines didn’t disappear in 2005. They were still in production for the Holden VE and W models and the LS6-powered Cadillac CTS-V, while the Chevrolet Performance division continued to offer both engines. In fact, Gen III engine production continued for new vehicles through 2007, so General Motors offered both the Gen III and IV engines during the mid-2000s.
In 2006, the ultimate Gen IV engine, the LS7 installed in the Corvette Z06, took to the streets. 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 over 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 (for the aftermarket) the LS364 carbureted Gen IV engine and the LSX bare block for retrofitting and swapping.
To further push the Gen IV platform, General Motors stepped up the game with two new ultra-high-performance engines in an effort 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 bhp (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.
1996 Nissan 240SX SE
Proving to be a popular swap platform, this Nissan 240SX owned by Blane Burnett devours any autocross course and track upon which it is unleashed. This is due in part to the performance heritage of the S14 platform, but the real reason is the LS2 stuffed between the fender wells. This Nissan was used in the development of the LS swap kit that Holley Performance now offers as an off-the-shelf system.
The goal was to build the Nissan into a potent autocross car that was affordable, had good handling out of the box, and was easy to work on. The factory weight bias of the 240SX is 60/40, but the LS2 only added 50 pounds to the nose of the car. With the addition of a rollbar in the back, the bias remained the same. The aluminum-block engines offer weight savings over the iron blocks of the Gen III Vortecs. An LS7 certainly swaps into the Nissan, but the dry-sump oiling system can create some fitment issues due to the smaller engine bay. Supercharged versions of the LS engines would have been an excellent option for the 240, but hood clearance might be an issue. Keeping the stock hood adds to the sleeper effect of the project.
The beauty of the LS platform is that it is almost like Legos for gearheads. You can start with just about any base engine and swap parts back and forth until you get what you want. You are not stuck with one particular accessory drive, oil pan, or induction system with any one particular block. Most of the parts swap across all generations and sizes of LS-series engines.
This LS2 was sourced from a salvage yard 2005 GTO. The GTO accessory drive was swapped out for the Cadillac CTS-V drive. The GTO drive has a wide A/C compressor position, and although the CTS-V drive is very similar, the A/C compressor position is much tighter to the block, allowing for more chassis clearance. The water outlet also moves to the upper driver’s side of the water pump. One other benefit of the CTS-V drive is that the pulleys are closer to the engine, increasing the front clearance by 3/4 inch. The stock T56 transmission is mated to an LS2 engine.
Installing the LS2 was a straightforward process using Holley-designed components. The motor mounts are a two-piece design. The block mounts have a raised platform for the intermediate bushings. The mounts are connected to the factory chassis mounts using cylindrical intermediate polyurethane bushings, which are made by Creative Steel. Out back, the Holley-fabricated transmission mount for the T56 transmission bolts directly to the chassis.
The transmission was converted to the F-Body shifter using the internal shifter receiver inside the T56. An LS7 clutch kit and RAM 19.2-pound flywheel were used to connect the T56 to the LS2 for spirited shifts on and off the track. The clutch is operated through a Wilwood 3/4-inch master cylinder with an adapter kit from Street Elite Performance.
To adequately cool the LS2, Blane installed a Hinson LS aluminum radiator. This radiator is a drop-in for the 240SX, maintaining accessory drive and hose clearance. It uses a set of electric fans to supplement cooling.
To complete the project, he upgraded the suspension with SPL Pro Suspension components, including tension rods, tie-rods, and a set of Stance GR+ Pro coil-over shocks. The 240SX rides on Nitto NT-05 tires with 17x10s out back and 17x8s in front.
The 240SX is now quite quick on the autocross. In its first outing at LSFest, it ran a 44.59 in the autocross. For comparison, Randy Johnson’s pro-touring Camaro ran a best lap of 43.90, and that is a dialed-in track car. Only .69 second separate the two, and the 240SX had not been dialed in. That is one slick Nissan.
Written by Jefferson Bryant and Posted with Permission of CarTechBooks