fuel system is another critical component of an LS swap because nearly all of them require return lines and electric pumps. You can use either an in-tank pump or an external electric pump, both have benefits and drawbacks.
You will find information on all of these topics and many more inside this book to help you wade through the world of Swapping LS-series engines Into GM A-Body cars.
MODERN V-8 MASTERPIECES: THE LS- AND LT-SERIES ENGINE
Development for the Gen III engine began in 1991 after the short-lived LT1/LT4 engine failed to meet GM’s performance expectations. General Motors essentially started from square one to create the new Gen III V-8 engine, which shared very little with the original small-block Chevy LT1/LT4 platform 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. A series of high-performance Gen III/Gen IV engines followed it.
An assembly technician installs components on each Gen III/IV powerplant. All Gen III/IV engines are distributorless, and all but one are fuel injected. If you are buying a used engine, you need all the wiring and electronics for almost every engine swap, unless you are going to use an aftermarket controller. (Photo Courtesy General Motors)
Although many refer to these as “LS” engines, the official nomenclature is Gen III and Gen IV. These remarkable engines produced class-leading performance and fuel efficiency. Street rodders, muscle car enthusiasts, and even sports car aficionados recognized the potential of the potent, compact V-8s and sought 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. It seemed the horsepower wars from the late 1960s were back again. In addition, Gen III/IV engines transformed Chevrolet Performance’s marketplace and they released a full complement of high-performance parts for these powerhouse engines.
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 a stroll through the local salvage yard, a website visit, or a phone call to your local dealer. You can select a “take-out” engine from a damaged or totaled vehicle in a salvage yard, build an engine from component parts, or pick out a crate engine with a warranty from many different LS engine dealers and Chevy Performance. Many different models of these venerable engines are available from a variety of sources.
Gen III: A Revolution in V-8 Performance
All aluminum and cast-iron blocks built from 1997 through 2004 are basically the same. However, there are some minor differences within this time frame, including an important internal difference. The outside diameter (OD) of the camshaft bore was changed in 2004. Although the cam itself remained the same, the bearing OD changed, and required a different set of cam bearings.
General Motors utilized the Gen III platform for the full range of GM trucks. 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 have the same aluminum cylinder heads. The Vortec truck engines have proven to be a popular swap because of their abundant availability. You can pick up a Vortec Gen III for next to nothing.
The scalloped holes at the top right side of the main webs on the block illustrate the crankcase breathing holes. This promotes proper ventilation for the air and oil vapor in the Gen III/IV engines. (Photo Courtesy General Motors)
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). With AFM, the engine alternates firing of the pistons among all eight to as few as four pistons, saving fuel and reducing emissions. Although the technology has been offered on the Gen IV platform, this engine series was designed to accept Variable Valve Timing (VVT) and to accept three valves per cylinder.
But that did not mean the Gen III disappeared from production in 2005. The LS1 was still in production for the Holden VE and W models and the LS6-powered Cadillac CTS-V, while the Chevy Performance division continued to offer both engines. In fact, Gen III engine production continued for new vehicles until 2005 when two all-new engine platforms were released: the Gen IV LS2 and LS4.
Pumping out 505 hp, the LS7 was the first dry-sump LS engine, and it’s a favorite for swap projects because you don’t have the oil pan clearance issues that you have with a wet-sump engine. In addition, this fourth-gen engine is one of the most powerful naturally aspirated engines and is standard equipment in the Corvette Z06 and Camaro Z28. (Photo Courtesy General Motors)
Cadillac and Chevrolet needed an engine to turn the CTS-V and ZL1 Camaro into street demons, so General Motors came up with the LSA. The slightly smaller Eaton supercharger reduces the overall output to 556 hp compared to the LS9. The LSA is also available as a crate engine. (Photo Courtesy General Motors)
The LS9 is the ultimate LS powerplant, making 638 hp with the intercooled supercharger. When it was released, it was the most powerful production engine ever made by a U.S. manufacturer. It was installed in the ZR1 Corvette and the ZL1 Camaro. The 6.2-liter engine is available as a crate engine from GM Performance. (Photo Courtesy General Motors)
In 2014, General Motors introduced the LT1, the next evolution in small-block pushrod engine technology. Upgraded from the LS-series, the LT-series engines share some basic architecture, but are a completely new line of engines.
The biggest advancement in the LT series is direct injection. Similar to diesel fuel systems, the mechanical pump pressurizes the fuel to more than 2,000 psi and injects it directly into the combustion chamber, ensuring there is no issue with atomization and yielding absolute control over the engine’s fuel use. (Photo Courtesy General Motors)
In
