LS-Engine Swap Part II: Getting Fueled, Fired, And Cooled

In our first installment of this two-part article showing you what LS-swap parts you need and where to get them when swapping an LS engine into a classic Chevy, we covered engine and transmission mounting, headers, and accessory-drive systems. As good as that information is, there is still a lot more that you need to know when swapping an LS engine into your classic.

While you might have the engine in place, you need to make sure that it has fuel and spark for ignition, and you need to make sure that it will stay cool when it is running. That’s where this article comes in.

In this second installment of LS swap parts you need for an LS upgrade, we focus on options for connecting the ignition, fuel delivery system, and cooling components to complete the swap.

If you’re ready to continue installing your LS engine, take a look at the following list of parts you will need for the swap, and then get to it. Once you know what you need, the swap is easy.

There are a lot of considerations when contemplating an LS swap. Hood clearance, power and looks all play a part. – Bill Tichenor, Holley Performance

 

Fuel Delivery

There are two ways that you can get fuel into your LS engine — EFI or a carburetor. When it comes to fuel injection, you can either retain the factory system or add an aftermarket system. There are also intakes available that allow the use of a carburetor on an LS engine, but some guys feel that installing a carburetor on a computer-controlled engine is counterintuitive. Nonetheless, it is a viable option.

Carbureted

When it comes to carburetor-style intakes that are designed for the LS engine, there are several options available from two main companies: Holley, and Edelbrock.

Holley

Old school tunnel ram for new technology.

Holley

It doesn’t matter whether you are looking for an intake that will support a single carburetor or a tunnel-ram style dual-quad intake for your LS swap, Holley Performance products give you a choice. Their single-plane carbureted intakes are lightweight, and the runner design of the intake gives a broad power band from 2,500 through 7,000 rpm. This design has the lowest carburetor mounting flange height possible, without sacrificing power. While the intake holds a single 4150-style carburetor, a throttle body could easily be used.

If you are working on an LS3 or L92 engine, you have the option of Holley’s Hi-Ram intake. Holley’s LS3/L92 Modular Hi-Ram is similar to a tunnel ram, and features outstanding power-building potential when used on high RPM engines that are either normally aspirated or are using forced induction. The base is a modular design that accepts a wide range of carburetor and fuel injection tops. This intake is best suited for 6.0-liter and larger engines that are reaching maximum power between 7,000 and 8,000 rpm.

Edelbrock

LS swap

Edelbrock also has various intakes that are designed for the LS1. First up is their RPM intake. This intake gives your LS decent power and a broad torque curve from 1,500 through 6,500 rpm. They accept a single 4150-style carburetor and fit under most hoods. If you are looking for a single-plane intake that makes more power in the upper RPM range, the Victor Jr. might be just what you need. This high riser single-plane intake is capable of supporting engines with up to 600 hp. The Victor Jr. is available with either a 4150- or a 4500-style carburetor mounting pad. Keep in mind that hood clearance will be an issue when using this intake.

EFI

The LS engine comes with fuel injection from the factory. For this reason, many enthusiasts feel that it needs to be retained. But if you do decide to keep the factory fuel injection, just know that getting the computer and all of the wiring with the engine when you buy it will be a big help during the installation. But, if you want to upgrade your LS’s factory EFI system, you have choices.

Ebrock Pro-Flo

The Pro-Flow intake is capable of delivering smooth power all the way to 7,000 rpm.

Edelbrock

If you prefer the old-school look of a tunnel ram, the Pro-Flo XT LS intake will give your engine a large plenum to draw from, and tapered runners designed to help with port velocity.

If it’s a street car, then a dual-plane intake is the best for drivability.–Eric Blakely, Edelbrock

This intake has the potential of delivering great horsepower numbers, and a broad torque curve throughout the 1,500 to 7,000 rpm range. The intake is designed to accept a 90 mm throttle body, and according to the folks at Edelbrock, this intake manifold produces 30 more horsepower at 6,500 rpm than a stock LS6 intake manifold (Editor’s note, the intake is sold a la carte. You will need to purchase the fuel rails and injectors separately).

LS swap

MSD

Although MSD is known for its ignition systems, the company has proven they are just as adept at designing and building LS intakes. The AirForce intake optimizes the available plenum volume and uses improved flow paths over the stock intake into each runner. The runners feature a bell-shaped opening to increase and disperse air flow evenly into each runner. This helps equalize and maximize airflow.

The MSD intake is a two-piece molded design that allows for porting and modifying of the runners, and the polymer construction minimizes the intake’s weight and reduces heat absorption. The AirForce intake will accept factory throttle bodies, as well as aftermarket designs up to 103mm. The intake can also be used with most aftermarket fuel rails, factory GM fuel rails, and MSD’s Atomic LS fuel rails.

FAST

LS swap

Fuel Air Spark Technology (FAST) developed this polymer intake manifold for GM LS-based engines that have been shown to deliver substantial horsepower increases in multiple applications. The intake manifold features a modular design that affords those wanting to port the intake a fast and easy disassembly. The runners are removable to facilitate porting.

The FAST intake is lighter and has improved heat-dissipating characteristics over other aluminum designs. An added bonus is that if you want to add nitrous oxide to your engine, there are integrated bungs for the nozzles. The intake allows the use of factory accessories without modification or clearance concerns.

EFI Hybrid

You may know that you want to install fuel injection on your LS engine, but the factory look is lost on you. Let’s face it, your car is a classic and you like the look of an open-element air cleaner. Okay, we have you covered. All three of the above-mentioned companies also offer stand-alone throttle body EFI kits that will fit a carburetor-style intake.

Fuel Supply

We hope you didn’t forget that no matter how you get fuel into the engine, you first need to get it to the engine. If you decide to run fuel injection on your LS swap in your classic, you will need to up the delivery pressure of the fuel that is getting to the engine. Typically, if you have anything less than 45 psi of fuel pressure at your EFI rails or throttle body, the fuel injection system will not work. Don’t get too concerned, there are two ways that you can overcome this situation. One is to install a custom fuel tank with provisions for running fuel injection, and the other is a stand-alone sump system.

Custom Fuel Tanks

LS swap

The Rick’s Stainless Tanks aftermarket fuel is hand-fabricated and welded, and bolts right into the factory location.

Rick’s Stainless Tanks makes custom fuel tanks that are designed to fit directly into a classic Chevy that is receiving a late model, fuel-injected engine. The tank comes completely baffled to keep the fuel from sloshing around, which can cause aeration issues. The tank even includes a fuel pump that is ready to run, and will easily support engines up to 450 hp. What’s more, the fuel pump is replaceable and can be found at any GM dealer or most parts stores.

FiTech

The FiTech Go EFI Kit makes installing EFI on a previously carbureted application a no-brainer.

Keep The Stock Tank

If you don’t want to change your tank, Fuel Injection Technologies has what they call the Go EFI Kit which is designed around a portable sump. When mounted in your engine compartment, the fuel line that originally went to your carburetor is now connected to the “in” port of the sump tank. A supplied high-pressure hose is then plumbed from the tank to the inlet port on your EFI fuel rail or throttle body. Here is how it works: your stock fuel pump feeds low-pressure fuel to the FiTech sump tank, which is then delivered under high pressure to the throttle body or injector rails.

Aeromotive

aeromotive-phantom-fuel-pump-system-install

With some minor cutting, the Phantom pump fits virtually any stock tank.

If you want or need to keep your car’s stock fuel tank, you do have another option. Aeromotive has what they call the Phantom EFI Fuel System, which includes all the components you need to create a complete return-style EFI fuel system by slightly modifying your existing fuel tank. The Phantom system does require you to cut a hole in your existing tank in order to mount the internal pump system. According to Aeromotive, these systems are great for use on engines that are building anywhere from 300 to 700 horsepower. Although these in-tank systems come with everything you need to install the in-tank parts, you will need to supply -06 AN-style fuel hose and hose ends to connect the pump to the engine.

Ignition

What good is getting fuel to the engine if there is no spark to light it off? Just like with fuel delivery, there are different ways to get the spark to the cylinders depending on the type of swap you’re doing. If running EFI, you will need a different electronic controller than if you are running a carburetor.

Factory EFI

LS swap

The Painless Performance wire harness is an easy wiring solution for your swap.

If you are planning to keep the factory-style intake and fuel injection, then try to get the factory computer and wire harness when you get your engine and transmission. Although many of the wires in the stock harness will not be required since the engine is going into a classic car, they can be eliminated. Modifying a stock wire harness to fit your application might sound like a daunting task, and if you are not sure you want to tackle the job, just get the computer with the engine and transmission. As long as you have the computer, you can get a wire harness from a company like Painless Performance. Painless has harnesses that are designed to be used when LS swaps use mechanical throttle bodies, drive-by-wire systems, or other LS fuel-delivery options.

FAST

FAST Contoller

FAST’s EZ plug-and-play ignition controller makes lighting the fire in your LS engine’s cylinders a snap.

If the factory computer is not available with your engine, then FAST’s EZ-LS ignition controller is a low-cost and proven ignition option for any LS-engine swap. The controller is plug-and-play (includes a wiring harness) and can be mounted virtually anywhere because it is waterproof. In addition, they are compatible with stock LS crankshaft and camshaft sensors. The EZ-LS ignition kit is designed to be user-friendly, and uses a quick setup option that doesn’t require a laptop or specialized tuning. The kit adapts to 1997 through current GM coil-near-plug ignition systems, and both 24- or 58-tooth reluctor wheels. Unfortunately, the FAST EZ-LS controller is not compatible with LS-truck finned coils.

Carbureted/Throttle Body EFI

We are including throttle body EFI in this section because when you get your EFI kit from whomever you choose, it comes with the EFI controller. Regardless of whether your engine is carbureted or throttle body-injected, an ignition source is needed.

MSD

IMG_5049

The MSD controller is compatible with both carbureted and fuel-injected applications.

The 6LS and 6LS-2 ignition boxes will work with engines using either EFI or a carburetor. With these controllers, you can adjust the timing advance curve to suit your engine’s needs. You also get a programmable two-step RPM limiter, a programmed vacuum advance curve for cruising economy, and even a timing-retard feature if you want to add a little nitrous oxide. The MSD box is available for both 24- and 58-tooth reluctor wheel ignition systems.

Cooling

In case you didn’t realize it, your stock 1960-something radiator will not work with your swap. Unfortunately, the upper radiator hose connection on your classic radiator is now in the wrong place for an LS swap. Small and big-block Chevrolet radiators have the upper hose connection on the driver’s side and the lower connection on the passenger’s side of the radiator. When installing an LS engine, both connections should be on the passenger’s side of the radiator to facilitate hose connections.

Cool

This Be Cool Cooling Module makes installation easy.

When doing our research, we found that the easiest way to find a radiator is to look through the Jegs website. While there, we happened to run across this Be Cool LS-Swap Cooling Module. The module is vehicle specific and comes complete with the radiator, electric fan(s), wiring harness with 40-amp relay(s), and a billet coolant recovery tank. These modules are a drop-in fit, have the correct sized coolant inlet and outlet, and even come with properly sized LS steam ports. It couldn’t be any easier.

Well, there you have it. With this final installment of our two-part article, swapping an LS engine into your classic Chevy just got a whole lot easier now that you know what you’ll need to complete the project.

Article Sources

About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
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