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Chevy Chevelle LS Engine Swap - Swaptastic!

Dropping An LS Engine Into Your Vintage Chevy Can Be A Painless Process If You're In The Know.

By Michael Copeland, Photography by From The Super Chevy Archives

Captions and Introduction by Steven Rupp
Editor's Note: Michael Copeland is General Motors' foremost authority on LS swaps into vintage iron. His title is Project Manager--Concept and Vehicle Integration, GM Performance Division. We are grateful to have him as a SUPER CHEVY contributor.

Since it first hit the automotive scene back in 1997, the venerable LS1 and its various incarnations have quickly become the go-to engines for EFI swap projects. While the LS platform hasn't surpassed the good old first-gen small-block in terms of how many old Chevys it's powering, it's certainly becoming more prevalent each year. Part of this growth is because the aftermarket industry is making it easier than ever to stuff this aluminum powerplant into any Chevy, or anything else for that matter.

Even as recently as five years ago it was a challenge to get an LS engine into old Detroit iron. Engine mounts had to be fabricated, and in some cases headers had to be custom bent to accommodate the engine's unique architecture. Guys have been retrofitting LT1s into cars for some time, so grafting in an EFI capable fuel system wasn't so bad, but it still required fabrication and creativity. Then there was getting the electronics in order. Programming software for the computers needed to run the LS1 were archaic by today's standards and finding people that knew their way around the code was tougher than finding out where Jimmy Hoffa is stashed.

But, as they say, "that was then and this is now." It's 2009 and getting LS power under the hood of your old Chevy is nearly painless. Where once parts needed to be whittled out of steel using a penknife, those parts are now just a phone call or web hit away. And where once the aftermarket only supported the first-gen Camaro it now caters to everything from Tri-Fives to Chevelles. Is it as easy as dropping in a carbed small-block? Not yet, but the benefits of all that EFI-fired goodness is worth the small amount of extra work, and cash, required to make it happen. There are even parts available to make these engines carbureted if that's your bag.

With the aftermarket making the swap easier, that leaves the other common complaint about LS swaps--cost. Can you empty your wallet and max your credit dropping in an LS engine? Hell yeah, but, like most things in life, how expensive it ultimately turns out to be is completely up to the guy holding the wrench. More people making more parts equates to more competition and that ultimately drives down the cost of parts. It also helps that the creative folks out there have had years to figure out how to do it cheaper. If you want that sweet drive system from March Performance or Concept One, but are short on funds, then, thanks to GM, you still have a plethora of LS drive systems lurking in scrap yards. Not as fancy as the billet baubles, but dirt cheap and quite capable of getting the job done.

It's the same story with all the other systems involved as well. Can't afford coated long tube headers yet? Easy: Make due with some factory exhaust manifolds. Whether you have enough cash to buy the best of the best or you're on a restrictive budget, dropping an LS engine into your ride is an attainable goal.

But even more important than parts or cash is knowledge. Since 1997 GM has released quite a few versions of the original LS1 and instituted a host of changes, some not so subtle. Since LS-based mills now reside under the hoods of so many different GM vehicles, it's imperative to know "what's what" in terms of items like oil pans, computer systems, and various other differences. Being well-versed in all things LS will keep you from making costly mistakes.

To get the 411 on LS swaps we went straight to the source, General Motors, and asked Michael Copeland what he felt was the most important info a gearhead would need to know when looking to tackle a swap. So read up on what's become the most successful engine ever put out by GM. After all, knowledge is power.

From The Desk Of Michael Copeland:The GM LS Series of engines is a popular choice for use in almost any vehicle not built with one. Virtually every vehicle GM has built in the last 100 years could benefit from swapping in an LS engine. And why not? GM has built millions of them. They make great power, deliver amazing fuel economy, are compact, and lightweight. Not to mention, with all the factory and aftermarket support, these engines can be built to meet almost any requirement. Here are some of the "most common" topics that come up when discussing LS swaps.

Generation Identification
Currently, there are Gen III and Gen IV versions in the LS family. The easiest way to determine which version you have is the location of the cam sensor. Gen III engines have the cam sensor located in the block at the rear of the intake manifold. Gen IV engines have the cam sensor located in the front cover. Gen III engines have 24x crank sensors, and Gen IV have 58x. The 24x sensor has a black connector, and the 58x has a gray connector. Engine controllers must be matched to this sensor or the engine will not run. Both cam sensors will work with either crank sensor, but the connector has to be repinned to match the engine controller.

Engine Size
All LS engines, from the 4.8-liter through the 7.0-liter, are the same external size. This is true for even the maximum horsepower versions from GM, including the supercharged LS9 and the LSX 454 crate engine. All production LS engines have the engine size cast into the block. There are different power levels available in LS engine sizes, and the only way to identify which version you are looking at is to check the vehicle identification number stamped in the block.

There are aftermarket blocks available (Dart, World Products), both in short- and tall-deck versions. GM Performance Parts has a standard-deck LSX block, and joined this group with a tall-deck version in early 2009. RHS (a division of Comp Cams) will soon have engine blocks available as well. These blocks allow you to build LS based engines all the way to past 500ci. With some of these aftermarket race blocks, the deck is higher, but the rest of the block shares common dimensions with the production LS engine.

Engine MountsAll LS series engines have the exact same mounting bosses for the engine mounts. This makes swapping any LS for another LS a bolt-in. There are many aftermarket companies making adapter mounts to install an LS into almost any vehicle made. While most share the same basic design, there are some differences. Make sure you use the adapter mount the manufacturer recommends, and install it per the instructions. Not following their directions can make the engine sit in a different location, this can make other components like headers or oil pans difficult to install. Before purchasing additional components, you should contact the mount manufacturer to determine which components were used in the design of their mounts. Many of these mounts locate the engine in slightly different locations, and unless you verify which parts work with their mount, they might not fit without modification.

Oil Pans
There are numerous versions of oil pans available, from both GM and the aftermarket. Most are rear sump designs, except the GTO and Holden, which use a front sump. Almost every vehicle uses a differently designed pan, so selecting one for your specific application is difficult. Early Corvettes used a "wing" pan. It is difficult to install in most vehicles, but is a good choice if your vehicle will be used for road racing. The "F" car and CTS V oil pans both work well for engine swaps. The "F" car pan has a shorter sump front to back, and is the most popular. The aftermarket offers a number of different style oil pans for various applications. Companies that can get you set up include Milodon, Autokraft, Moroso, and Canton, just to name a few. They all offer oil pans for engine swap applications, but remember to match the oil pick-up, and dipstick to the pan.

When you install the oil pickup, make sure the tube and O-ring seal are straight in the oil pump. If not, you can have low oil pressure and damage your new engine. All LS-based engines use an O-ring-style oil pan gasket. As long as it is not damaged, it can be reused. Even some aftermarket pans, like the one from Canton, use the GM O-ring gasket.

Transmission Bolt Patterns
All LS-series engines share a common transmission bolt pattern. It is the same as the traditional Chevy pattern, with one missing bolt. The center bolthole on the passenger side is not drilled or tapped in production blocks because the hole would protrude into the water jacket. This bolt can be left out if you are using a traditional transmission or bellhousing. If you have a LS-based transmission bellhousing, it will not have a hole for a bolt. Some aftermarket blocks and GMPP LSX blocks have this bolthole and if possible it should be utilized.

Flex Plates And Flywheels
The rear snout on the crankshaft of all LS series engines is 400 thousands short compared to traditional small- or big-block Chevy engines. If you are using a LS engine/transmission package, there is no issue. If you are installing a traditional GM transmission on LS engines, changes must be made to locate the flywheel or flexplate in the correct location. Spacers are available that relocate the flywheel to the traditional location. If you use the spacer, make sure you install a long rollpin into the alignment hole where the flywheel bolts on. This will help prevent the flywheel from coming loose.

Also, always use new bolts or Loctite on used bolts. The better option for high power applications is to use a flywheel or flexplate designed for this application. They are designed to locate components in the correct location. If you use one of these flexplates, a spacer must be installed on the snout of the converter to extend it. This allows the converter to retain the pilot in the end of the crankshaft. Not using this can cause transmission failure.

If you are installing a stick shift transmission, there are two locations in the rear of the crankshaft for pilot bearings. One takes a small bearing, designed to sit deeper in the crank. The other bearing is larger, and sits closer to the transmission. Make sure you measure the input of your transmission and install the correct bearing. Another area or concern is the throw-out bearing. Most people use hydraulic throw-out bearings, but regardless of which style you use, measure the travel to make sure you have enough travel to fully release the clutch.

If you do not have enough travel, the clutch will drag and you will not be able to shift when the engine is running. Also make sure the throw-out bearing is not too close to the clutch. If this happens the clutch cannot fully engage and will slip. Even if you are using production LS components with an aftermarket clutch, this must be checked. This is a critical area, and no one wants to remove the transmission to repair it after installing a new engine.

Accessory Drive Systems
Almost every vehicle GM builds with a LS engine has a different accessory drive. Most of the car-based systems interchange. Because of availability, the most popular systems used in engine swaps are the Corvette and the "F" car. Another popular system is the CTS V. It tucks in closer to the engine, and works well in limited space applications, like an LS7 Solstice.

There are a number of aftermarket kits available to fit many applications. If you prefer factory components, GM Performance Parts offers a complete CTS V (PN 19155066) and Corvette (PN 19155067) accessory drive kits. They come with every component required, including the bolts. Truck-based accessory drive systems do not work well with car intake manifolds since the throttle body interferes with the alternator bracket.

Remember, the crank pulley must match the accessory drive system you are using. All production A/C compressors are located low on the passenger side. In many applications it will hit the frame in this location. There are a number of aftermarket companies that make brackets to relocate the A/C compressor to a location above the thermostat housing. This can eliminate the requirement to modify the frame.

Cooling Systems
All LS water pumps share a common bolt pattern, and will interchange between engines. This allows you to use an LS3 water pump in space-confined applications. It works with most accessory drive systems, and is much shorter (over one inch) on the front compared to a LS1 pump.

Both radiator hoses come out on the right side of the engine. This makes it difficult to install the upper radiator hose in some applications. Using a dual-pass cross-flow radiator allows both hoses to hook up on the passenger side. An additional benefit to dual-pass radiators is they keep the coolant in the radiator longer. This allows the fan to remove more heat, and it increases the ability of the radiator to cool more efficiently.

All LS based engines have a small hose connected to the front of the cylinder heads. In some applications, it is hooked to the lower left side of the throttle body, then to the radiator. Either way, this tube must be hooked to the radiator in the area of the upper radiator hose. It vents air from the top of the cylinder heads, and not hooking it up can cause engine damage.

Closed cooling systems, with a pressurized overflow bottle, cool better than a standard system with an open overflow bottle. The additional coolant in the bottle, plus the higher pressure, allows the system to cool more efficiently. This type of system is used in the Cadillac CTS-V, Pontiac Solstice, as well as other GM vehicles. They make good candidates to salvage used parts from. If you choose to install one of these systems, the lower line from the bottle should be tied into the return heater hose (the most forward 3/4-inch nipple on the water pump housing) on a LS engine. The vent hose from the cylinder head should be hooked to the small upper nipple on the bottle.

All production LS engines are built with a 195-degree thermostat. Never remove the thermostat from an LS based engine since it's designed to direct flow through the engine, and removing it can cause engine damage. You can run a lower temp thermostat, but remember the engine controller uses engine temperature to determine fuel and timing curves.

Fuel Systems
All production LS engines are fuel injected. The engines are available with both "return" and "returnless" fuel rails. Early ('97, '98, and some '99) LS engines were equipped with return-style systems. These have two nipples on the fuel rail, the supply is 3/8-inch and the return is 5/16-inch. There's a regulator on the fuel rail that maintains fuel pressure. This regulator uses an internal spring and manifold vacuum to adjust fuel pressure based on engine load. Later LS engines ('99 and up) have a returnless-style fuel system.

These engines have one 3/8-inch supply line to the rail. A regulator must be installed before the fuel rail to maintain 56psi of pressure. The engine controller is responsible for all engine performance functions, with standard calibrations based on 56psi. Pressures above or below this number can cause engine performance issues.

Intake Manifolds
There are a number of production-based intake manifolds, as well as a number of aftermarket units. LS1, LS6, and truck manifolds (excluding the 6.2L) interchange. These engines share a common intake gasket design. The LS6 intake is a popular upgrade for LS1 engines and adds 10 to 15 horsepower. The truck intake makes more torque at low rpm, but in modified applications they don't make as much horsepower at high rpm. They can be an advantage on a heavy vehicle, but hood clearance can be an issue. The LS2 intake can be used as well, but the MAP sensor was moved from the back to the front of the intake, so an adaptor harness is required.

The 6.2 L76 intake manifold can be used if you are running L92 cylinder heads. These are the same heads and intake used on GM's new LS3 variant. This intake was designed for use on Holden vehicles equipped with the L76 engine which is common with the L92 truck engine.

The LS7 intake is a stand-alone component, and should only be used with LS7 heads due to the unique intake port configuration.

As a side note, all LS-based intake manifolds can be installed in either direction. The bolt pattern, and port design allows the intake be rotated. This can be important for some kit car, or front wheel drive swaps.

In addition to the wide array of GM intakes, there are also a few aftermarket intakes from companies like FAST and Weiand that have been shown to add extra power to any LS engine.

ElectronicsWe could write an entire story on all the differences with electronics used to make an LS-based engine run, and if there is enough interest we will. For now, there are multiple sources for wiring harnesses and engine controllers. Everything exists, from a kit to install a traditional distributor and carburetor to full racing electronic control systems. You can use modified factory components, or purchase one of the many kits designed for your specific engine.

For the best all around performance, and ease of installation, purchasing a complete kit is a good choice. These kits come with all the components required to make your LS engine run, and can be hooked up with as few as four wires. Many of the advertisers in this magazine offer simple to install systems that will get your LS-powered vehicle on the road. The old days of an LS swap being rocket science are long gone and today it's easier than ever.

GM Performance Parts
AFCO / Dynatech
Hooker Headers / Holley
American Touring Specialties/ATS
Pace Performance
Billet Specialties
500 Shawmut Ave., Dept. SC
La Grange
IL  60526
Racing Head Service
Canton Racing
Rick's Hot Rods
Concept One
Rock Auto
Detroit Speed
185 McKenzie Rd., Dept. CHP
NC  28115
Stainless Works
Chagrin Falls
Doug's Headers
Speartech Fuel Injection Systems
Dept. 5.0
2700 California St.
CA  90503
Turn Key Engine Supply
Energy Suspension
1131 Via Callejon
San Clemente
CA  92673
Vintage Air
10305 I.H. 35 North
San Antonio
TX  78233
151 Industrial Dr.
MS  38603
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By Michael Copeland
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