Swap LS Engines into Chevelles & GM A-Bodies. Jefferson Bryant
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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 to meet fuel economy ratings while making significant horsepower numbers. In the past it was not possible for a small-block Chevy to make 400 hp and get 20 mpg. With an LS engine, it is not only achievable, it’s standard.
The 2013 Z06 Corvette has an LS7 that cranks out 505 hp and maintains 24 mpg highway and 15 mpg city for a combined 18-mpg average. A Gen I small-block Chevy cannot get close to those numbers. A stock Vortec 5.3-liter with an overdrive automatic can produce 350 hp and 20 mpg with a custom ECM tune.
These factors combined make the Gen III/IV engines the most popular swap since the original small-block Chevy hit dealers in 1955. With so many variations, there is sure to be a Gen III/IV engine to suit your application.
One of the most popular swaps is the 1964–1972 GM A-Body platform. This generation of vehicles covers every GM make (except Cadillac) and features the most popular muscle car models. These include the Buick Special, Skylark, Sportwagon, and GS. Chevrolet cars are the Chevelle, Concours Estate Wagon, Nomad, Malibu, and El Camino. Oldsmobile models include the F85, Cutlass, Cutlass Supreme, Vista Cruiser, and Cutlass 442. Fiercely independent Pontiac A-Body cars are the Tempest, Safari, LeMans, and GTO. The differences among models means different requirements for installing an LS or LT engine, most notably the frame stands for the motor mounts.
Performance Project: The “Take-Out” Procedure for a Vortec 5.3-Liter Salvage Yard Engine
Although some swappers purchase crate engines or salvage yard take-out engines, you can save a lot of money by finding a wrecked vehicle and yanking the engine yourself. GMC and Chevy trucks are the most abundant source for LS-series engines, but it’s important to find one with less than 200,000 miles on the odometer. When properly maintained, an LS engine can make 300,000 miles before needing a rebuild. An LS engine with 150,000 or fewer miles usually has a lot of life left and does not require a rebuild.
For this project, I bought a still-drivable 2003 Chevy 1500 truck with rear-end damage. The engine and transmission ran well and it could have been repaired. However, it had a salvage title and was a bargain at $500, so I went ahead with the swap. I rolled the truck into the shop and began stripping it down by removing the fenders. Although removing the fenders isn’t required, it makes accessing all the bolts much easier and the truck is slated for the scrap yard anyway. Within 10 minutes the fenders were off.