How many times have you heard that the days of building a decent engine from the junkyard are over?

That may have been true during the 80’s – during the Small Block Chevy days – and prior to the release of GM family of LS engines. Now, due to the fact that the LS is in “everything” – GM’s little lightweight powerplant that could, it has changed the way Chevy guys think about engine building. These LS V8′s are exactly what gear heads have been looking for: lightweight, compact and producing at least 1 horsepower per cubic inch with reliability and durability. And by the way, if you’re looking for good fuel economy and tons of aftermarket support in a basic platform that can rev high and pull hard from low rpm, and do all of that on pump gas without complexity or tons of maintenance, then digging through the junkyard for the right parts to put together a recycled LS engine might be for you.

Let’s say you’re a guy with dreams of big horsepower, but a wallet with a four cylinder stroke or maybe you’re a guy that just likes a challenge and likes spending time searching in the local junkyard.  Can you build a modern GM engine using junkyard parts that has decent horsepower and longevity?  We talked to a couple of the best LS engine builders on the planet to find out what junkyard parts it would take and what pitfalls to avoid in building a junkyard LS engine with muscle.

Our Experts:

Chad Golen, Golen Engine Service

Golen has 20 years of engine building experience with 17 years focused on LS performance engines. Golen Engine Service is operated in a 12,000 squarefoot facility in Hudson, New Hampshire, where a team of hand picked and home grown technicians produce high performance miracles for an elite clientele base. Among these customers, Golen has built custom engines for golf legend Jack Nicklaus and Jerry Onks. Golen’s LS7 engine work powered Onks’ road race Corvette to the 2010 Road America Championship.

Golen's clientele list includes Jerry Onks, whose C6 Corvette Road Race GT3 Racecar is powered by a Golen 427ci LS7 Race Engine.

Golen’s engines have also been purchased by D&S American Muscle for Mad and Daring Race Team of the Netherlands for use in their C6 Corvette GT3 Race Car, The crew at Golen’s is specialized in their respective areas which allows for a very high degree of experience in specific systems. Among the specialties, Golen’s Engine Service has a full staff of machinists and their own in-house dyno operator and tuner.

Billy Briggs, Briggs Performance

Briggs has been involved in building high performance GM engines for over twenty years and claims some of the most impressive accolades that an engine builder can earn. In the past few years, Briggs Performance has focused on building some of the fastest LSX drag racing motors that compete in the National Series. Briggs’ engines have powered winners across the nation, most notably in the LSX shootout in both drag radial and true street classes as well as Milan dragway’s heads-up drag radial and 10.5 outlaw classes.   According to owner Billy Briggs, “99 percent of our business is LS engines.”

Other accomplishments that Briggs Performance claim include the following:

  • First LS engine to exceed 2000 hp
  • First LS engine powered race car to run faster than 7.0 second quarter mile
  • First LS engine powered race car to exceed 200 mph in the quarter mile

Breakdown on GM’s LS Engines:

GM’s LS engine platform is often called the new small block Chevy and it’s entry into the marketplace signaled a higher performance era in GM motors with the same interchangeability that GM fans have come to expect. With almost a decade and a half in the market, the popular LS engine platforms have been showing up in the salvage yards in droves which means that cores can be found on the cheap. These engines have been showing up as engine swaps in just about every type of chassis imaginable.

If you’re inclined to take on the challenge of building one of these inexpensive powerplants from cores found in a wrecking yard, you should be a little familiar with the evolution of the LS Platform. To help with matters, we worked with Chad Golen and Billy Briggs on a down and dirty guide to LS Engines below, starting with the one that began the evolution, the LS1.

LS1

LS1

Showing up first in the 1997 model year C5 Corvette, this aluminum block engine was a departure from the previous small block Chevy engine platforms. Sharing very little in common with the previous SBC platforms, the LS1 created a buzz with automotive enthusiasts and hot rodders alike. Because of their comparatively small bores – 3.89 inches – LS1 blocks can only use LS1, LS6 and LS2 heads. Using heads designed for larger engines will cause valve-to-block interference. Transplanting an LS1 could become touchy because the 1997-2004 Vettes came with throttle by wire throttle bodies and electronics to operate them. You must have the accelerator pedal and TAC module from a 1997-2004 Vette that match the PCM programming to use the stock throttle body.

The 1998-2002 LS1 equipped Camaro and Trans Am cars used a pwm VATS system as an anti theft device. A VATS module in the steering column transmits a pwm signal to the ECM if the proper ignition key is inserted into the key switch. If the improper key is inserted, the system disables the injector pulses after 2 seconds of engine run time. When transplanting the engine from one of these vehicles, the VATS system must be defeated. Painless Performance offers a kit that will accomplish this.The 1997-2004 LS1 Corvettes use a serial VATS system. The ECM and BCM use serial communication which is not defeatable by an add on VATS module.

  • Displacement: 346ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree cathedral port
  • Compression: 10:1
  • Bore & Stroke: 3.900” x 3.622”
  • Specs: rated at 350 hp and 365 lb·ft used in the Corvette from 97-04. It was also used in GM F-Body cars with a rating of 305HP – 325HP.
  • Where to look: 1998-2002 GM F-Body Camaro Z28 and SS, Pontiac Formula and Trans Am, 1997-2004 C5 Corvette, 2004 Pontiac GTO.

Notes: 1997-1998 LS1 engines had perimeter bolt valve covers.

Casting number 12550592 was available in the 1997 Corvette in the first production year. In the 1998 Corvette, Camaro and Firebird model with the 12550592 had casting improvements for added strength.

Casting number 12559846 (1998-1999) had an improved cylinder liner design

Casting number 12559090 (1998) was a midyear revision with new cam bushing material.

Casting number 12559378, 12559846 and 12560626 were released in 2000 with a cored rear cover oil passage design change.

LS2

LS2

The LS2 was introduced as Corvette’s new base engine in 2005. Using “243” casting heads, a smaller camshaft and an additional 18 cubic inches. Compression was raised from the LS1 and a different intake manifold and larger 90mm throttle body were incorporated. The LS2 intake manifold featured a larger plenum and re-contoured runners. NASCAR used the LS2 as the basis for the Spec engine used in NASCAR’s Camping World Series East and West divisions in 2006.

What makes the LS2 popular with engine builders is that the block is compatible with the high flowing and desirable L92 cylinder heads. The larger, 4.00-inch bore of the LS2 enables it to use LS1/LS6 heads, as well as L92-style heads.

LS2 engines from 2005 Corvettes and 2005-2006 GTOs and Chevrolet SSRs with engine codes ZJA, ZJB, 5MC, YTA and 6MC all had 24X crank position sensor reluctor wheels. These LS2 engines can be operated with an LS1 ECM and a fuel injection harness from Painless Performance, along with an LS1 Corvette style accelerator pedal and TAC module.

LS2 engines in 2006 and later Corvettes were equipped with a 58X crank position sensor reluctor wheel. These engines can be operated with a Painless Performance fuel injection harness, an E-38 ECM and 2006 and later Corvette accelerator pedal.

  • Displacement: 364ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree cathedral port
  • Compression: 10.9:1
  • Bore & Stroke: 4.000” x 3.622”
  • Specs: rated at 400 bhp @6000rpm and 400 lb·ft @4400 rpm larger displacement of 5,967 cc (5.967 L; 364.1 cu in)
  • Where to look: 2005-2006 Pontiac GTO,  2005-2006 Chevrolet SSR, 2005-2007 Corvette, 2006-2007 Cadillac CTS-V, 2006-2009 Chevrolet TrailBlazer SS

LS3

LS3

The LS3 was introduced as the Corvette’s new base engine for the 2008 model year producing 430 hp @ 5,900rpm and 424 lb-ft @ 4,600 rpm without the optional Corvette exhaust. The LS3’s block is an updated version of the LS2 casting with a larger bore at 4.060” creating a displacement of 376 ci. The LS3 also used the highly desirable L92 cylinder heads and a more aggressive camshaft and revised valvetrain. The stock LS3 is fitted with a 2001 LS6 camshaft that is modified with more intake lobe lift. Other features included offset rocker arms, high flowing intake manifold, a slightly stronger block than the LS2 and larger injectors from the LS7 platform. The LS3 block can use any head except for the LS7 and C5R.

LS3 engines in 2008 and later Corvettes were equipped with a 58X crank position sensor reluctor wheel. These engines can be operated with a Painless Performance fuel injection harness, an E-38 ECM and 2006 and later Corvette accelerator pedal.

  • Displacement: 376ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree cathedral port
  • Compression: 10.7:1
  • Bore & Stroke: 4.065” x 3.622”
  • Specs: rated at 430bhp @5900rpm and 424lb-ft @4600rpm
  • Where to look: 2008-2012 Corvette, 2009 Pontiac G8 GXP, 2010 and up Chevrolet Camaro SS.


LS4

LS4

The oddball LS4 is a 325ci version of the Gen IV small block with a different bellhousing bolt pattern adapted for transverse front-wheel drive applications. GM shortened the crankshaft 13mm at the flywheel end and 10mm at the accessory drive end to shorten the length of the engine. The accessories are driven with a single serpentine belt and the water pump is mounted remotely to save space. It uses the same cylinder head as the Generation III LS6 engine. Unless you’re modifying a front-wheel drive car, the LS4 platform is of little value to hot rodders looking for an engine swap.

  • Displacement: 325ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree cathedral port
  • Specs: rated at 303 hp and 323 lb·ft
  • Where to look: 2006-2009 Chevrolet Impala SS, 2006-2007 Chevrolet Monte Carlo SS, 2005-2008 Pontiac Grand Prix GXP and the 2008 Buick LaCrosse Super.

LS6

LS6

The LS6 platform is basically a higher output version of the LS1 engine with the same capacities only with better heads (243 head castings). Originally only used in the high performance C5 Corvette Z06 model, the LS6 was later used in the Cadillac CTS-V for two years before being replaced by the LS2. The LS6 shared the same basic design as the LS1 but improvements like the windows cast into the block between cylinders for bay to bay breathing, increased main web strength, higher flow intake manifold and a cam with higher lift and duration were incorporated. The key features of this engine is the higher compression ratio, sodium filled hollow stem valves and revised oiling system. Because of their comparatively small bores – 3.89 inches – LS6 blocks can only use LS1, LS6 and LS2 heads. Using heads designed for larger engines will cause valve-to-block interference.

Transplanting an LS6 could become touchy because the 2001-2004 Vettes came with throttle by wire throttle bodies and electronics to operate them. You must have the accelerator pedal and TAC module from a 2001-2004 Vette that match the PCM programming to use the stock throttle body.

The 2001-2004 LS6 Corvettes use a serial VATS system. The ECM and BCM use serial communication which is not defeatable by an add on VATS module. Best option on these is to use a different throttle body / ignition system or carburetor.

  • Displacement: 346ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree cathedral port
  • Compression: 10.5:1
  • Bore & Stroke:  3.900” x 3.622”
  • Specs: The initial LS6 in 2001 was rated at 385 bhp and 385 lb·ft, but the engine was modified for 2002 through 2004 to produce 405 bhp and 400 lb·ft of torque.
  • Where to look: 2001-2004 Chevrolet Corvette C5 Z06 and 2004-2005 Cadillac CTS-V.

Casting number 12561168 for LS6 was the first year for bulkhead vent windows in #2, #3, and & #4 bulkheads which eliminated the need for 28.5 mm drilled vent hole.

LS7

LS7

The LS7, while based on the Gen IV architecture, has several major changes in it’s design. Inspired and influenced by Corvette’s Le Mans racing program, the LS7 incorporates some serious race engineering in the engine’s development. The block itself has larger sleeved cylinders with a longer stroke. The crankshaft and main bearing caps are forged steel for strength and the connecting rods are forged titanium with hypereutectic pistons. Heads feature Del West 2.20” titanium intake valves and 1.61” sodium filled exhaust valves.

The hardware on the LS7 alone is impressive but the engineering incorporated in the package is very advanced for a production motor. The LS7 features a dry sump oil system and CNC ported 12 degree head castings. The cylinder heads, with the larger valves, flow an incredible 370 cfm. These engines are hand built by the General Motors Performance Build Center in Wixom, Michigan. The bad news? You’re probably not going to find one of these in your local wrecking yard. LS7 blocks should be matched with heads designed for at least 4.10-inch bores; and 4.125-inch bores are preferred.

LS7 engines in 2006 and later Corvettes were equipped with a 58X crank position sensor reluctor wheel. These engines can be operated with a Painless Performance fuel injection harness, an E-38 ECM and 2006 and later Corvette accelerator pedal.

  • Displacement: 427ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 12 degree rectangle port
  • Compression: 11:1
  • Bore & Stroke: 4.125” x 4.000”
  • Specs: Rated at 505 hp at 6300 rpm and 470 lb·ft at 4800 rpm with a 7000 rpm redline.
  • Where to look: 2006-2012 Chevrolet Corvette Z06

LS9

LS9

It’s extremely unlikely that you’ll find a wrecked ZR1 Corvette in a junkyard, and if you do, you are going to pay for this high end salvage piece.  These factory supercharged engines are based off of the LS3 block because of the higher cylinder pressures created by the supercharger which requires thicker cylinder walls. If you are looking for a motor that pumps out around 600 horses, is emissions legal and will last for 100,000 miles, your best bet is to buy this crate engine from General Motors Performance Parts at a price tag just north of 20K.

  • Displacement: 376 ci
  • Block: Cast Aluminum
  • Heads: Aluminum with 15 degree rectangle port
  • Compression: 9.1:1
  • Bore & Stroke: 4.065” x 3.622”
  • Specs: Rated at 638 hp and 604 lb-ft
  • Where to look: 2009 and newer Corvette ZR1

LQ4 “Junkyard Special”

LQ4

Based on the LS engine, this 6.0 Liter truck engine was designed to bridge the gap between the new LS small blocks and Big Blocks for the truck applications. The major difference in the LQ4 engine is that they are cast iron instead of aluminum. Bolting a set of LS6 heads to the iron block, the LQ4 was born. The 1999 and 2000 model year engines had cast iron heads with all other model years sporting the cast aluminum heads. The beefy iron block and the 4.000” cylinder bores that can accommodate the GM L92 heads, make for some serious horsepower at budget prices. For junkyard engine builds, these are a very desirable engine. The LQ4 and LQ9 are the most common Gen III LS blocks, and are very desirable due to the big bore and durable iron construction. Some have made 1,500+ HP on this block.

All trucks manufactured with Gen III & IV engines have a serial anti-theft system.  This serial anti-theft system is only defeatable through ECM reprogramming.  You should plan on having the ECM re-flashed when installing this into your transplant vehicle.

  • Displacement: 366ci
  • Block: Cast Iron
  • Heads: Cast Aluminum or Cast Iron 15-degree cathedral port
  • Compression: 9.4:1
  • Bore & Stroke: 4.000” x 3.622”
  • Specs: Rated at 300 horsepower to 325 horsepower and 360 lb·ft to 370 lb·ft from the factory.
  • Where to look: 1999-2004: Chevrolet Express/GMC Savana, Chevrolet Silverado 2500, Chevrolet Suburban/GMC Yukon XL Denali, Hummer H2.

LQ9

Vortec Max LQ9

Marketed as the Vortec HO 6000 and later as the VortecMax, the LQ9 was a higher output version of the LQ4. Specially designed for the Cadillac line, the engine found it’s way into GM’s truck line as the VortexMax in 2006. The LQ9 featured a bigger cam and higher compression flat top pistons for an extra 10 horses and 10 lb-ft output over the LQ4. Like it’s predecessor, the LQ9 is a highly valued engine for budget rebuilds of stock engines that can be pushed to a higher horsepower level.

All trucks manufactured with Gen III & IV engines have a serial anti-theft system.  This serial anti-theft system is only defeatable through ECM reprogramming.  You should plan on having the ECM re-flashed when installing this into your transplant vehicle.

  • Displacement: 364ci
  • Block: Cast Iron
  • Heads: Cast Aluminum 15-degree cathedral port
  • Compression: 10:1
  • Bore & Stroke: 4.000” x 3.622”
  • Specs: Rated at 345 hp and 380 ft·lb from the factory.
  • Where to look: 2002-2006 Cadillac Escalade, Cadillac Escalade EXT, 2003-2006 Cadillac Escalade ESV, 2003-2007 Chevrolet Silverado SS, 2004-2005 Chevrolet Silverado and GMC Sierra (Vortec HO Edition only), 2006-2007 Classic Chevrolet Silverado and GMC Sierra VortecMax Option.

LY6

LY6

Another cast iron truck block, the LY6 is the replacement for the LQ4.  Sharing the same bore and stroke as the LQ4, the LY6 added variable valve timing which makes the powerband a little broader. These engines came from the factory with the high flowing L92 heads and increased compression. They may be too new to readily find in the wrecking yards, but patience and a lot of searching could reward you with a stock 352 horsepower block.

All trucks manufactured with Gen III & IV engines have a serial anti-theft system.  This serial anti-theft system is only defeatable through ECM reprogramming.  You should plan on having the ECM re-flashed when installing this into your transplant vehicle.

  • Displacement: 364ci
  • Block: Cast Iron
  • Heads: Cast Aluminum 15-degree rectangle port
  • Compression: 9.67:1
  • Bore & Stroke: 4.000” x 3.622”
  • Specs: Rated at 352 hp and 382 ft-lbs.
  • Where to look: 2007 to present: Chevrolet Silverado HD, GMC Sierra HD, Chevrolet Suburban 3/4 ton, GMC Yukon XL 3/4 ton.

L76

L76

Also referred to as the new VortecMax, the L76 is often considered the replacement for the LQ9 engine. The L76 is an aluminum block version of the LY6 that incorporates features like variable cam phasing and active fuel management. Other differences include a higher compression ratio and bigger camshaft. A second version of the L76 was manufactured with an LS style intake for the Pontiac G8 GT which dropped the variable valve timing feature.

All trucks manufactured with Gen III & IV engines have a serial anti-theft system.  This serial anti-theft system is only defeatable through ECM reprogramming.  You should plan on having the ECM re-flashed when installing this into your transplant vehicle.

  • Displacement: 364ci
  • Block: Cast Aluminum
  • Heads: Cast Aluminum 15-degree rectangle port
  • Compression: 10.4:1
  • Bore & Stroke: 4.000” x 3.622”
  • Specs: Rated at 366 hp and 376 ft-lbs in the truck versions 361 hp and 385 ft-lbs in the Pontiac G8.
  • Where to look: 2007-2009: Chevrolet Surburban, Chevrolet Avalanche, Chevrolet Silverado, GMC Sierra, GMC Yukon XL and 2008-2009 Pontiac G8 GT.

Searching the Junkyard

Before you even head out to the junkyard, it’s beneficial to identify the parts that you are looking for, know which vehicles are donor vehicles and set a parts budget. These three tips work inconjuction with each other and will help keep your project in the budget range.

  • For example, when you are identifying the components that you want to search for at the local junkyard, try to select parts that are more common.  Not only are your chances of finding a decent component better, but the larger the parts market is for the component, the cheaper the cost will be. The more rare a part is, the more you can expect to pay for it. Golen explained, “Doing an engine build with parts from the junkyard is going to take a person that is willing to do the homework, willing to ask questions and willing to do the legwork. Getting all the parts for a real strong performing motor from the junkyard can be done, and the complete project can be assembled at a cost between $2,000 to $2,5oo, but it’s going to take a sharp do it yourself guy that will put in the time.”

This LQ4 was rescued from a wrecking yard.

  • Once you have your parts list in hand, you’ll want to make sure you are prepared for the actual search. Bring a printed out list and even pictures in you could. An iPad or Tablet with WiFi would be even better!
  • In addition to the common hand tools and gloves, you will want to bring an inspection mirror, a magnet and a good flashlight. According to Briggs, “A flashlight and inspection mirror will come in handy when checking for casting numbers or the bottom side of the pistons. The magnet comes in handy when you are checking for metal deposits in the oil pan.”

An LS3 block is a rare junkyard fine but well worth it.

Searching For Parts..

The Block: Aluminum or Cast-Iron

LS blocks came in both aluminum and cast iron versions. with so many different engine blocks in the LS family to choose from, how do you decide?

“Cast iron is the ticket,” says Billy Briggs. “For a budget build, and from a performance standpoint, the LQ4 and LQ9 cast iron blocks are the way to go.  You’re going to have problems with a stock block if you try to push it too much but cast iron is the one that you can push the most without too much risk,” he added. Chad Golen also preferred the cast iron block for this type build, “Without a doubt, I would look for an LQ9 truck engine block. If you can pick up the entire complete engine with intake, ECM, accelerator pedal and harnesses, you’ll be miles ahead of the game.”

According to Briggs, “The LQ4 and LQ9 cast engines with their aluminum heads and composite intakes are well designed to work together and there is no reason to try and mix and match other heads or intakes for this type of budget build.” He quickly added; “You will want to get the wiring harness, computers, sensors and gas pedal with the engine when you pull it from the vehicle.  Don’t clip the wires and find out later that it costs you more in the long run to replace these electrical components and have them calibrated to your engine.” Golen added, “If you can’t get the matching heads for the engine block, it’s worth your time and the extra expense to find a set of L92 heads from a Cadillac 6.2 liter engine.”

LQ9 cast iron block.

Briggs says that the production blocks are stronger than most people give credit. “These blocks are pretty solid pieces that don’t have any inherent problems,” explained Briggs,” but when you go to put the heads back on, I wouldn’t use the GM MLS gasket. They are good but for 90 bucks you can put the FELPRO MLS gasket on it.” The bottom line on Gen III cast iron blocks is durability. To illustrate that point, Briggs said “If you bought a 6 liter truck motor, bought new rods and pistons, honed it out with plates, you could make 1,000 horsepower all day long.”

The LQ9 "317" casting number head. (Photo from LS1TECH.com)

A Word About Flex Fuel GM Trucks

General Motors manufactured full size trucks with two different types of flex fuel systems. The early type used from 2002-2005 utilized a fuel composition sensor (FCS).  This sensor measured the ethanol content and temperature of the fuel and sent a pwm signal back to the ECM.  The ECM applied this signal to a look up table which gave different commanded air/fuel ratios according to different amounts of ethanol in the fuel.  The Fuel injectors on these engines are larger than the non-flex fuel type and also use a different connector.

ECMs from these vehicles require the signal from a FCS in order to command the correct air/fuel ratio.  If there is no signal is present, the ECM commands an air/fuel ratio that would allow the engine to operate regardless of ethanol content in the fuel.  This default air/fuel ratio is  rich for 100% gasoline and lean for 85% ethanol. Aftermarket fuel injection harnesses can be purchased that allow keeping the flex fuel design with the addition of an FCS sensor and the matching ECU or the flex fuel design can be eliminated by changing the fuel injectors and changing the VIN on the ECM to a non-flex fuel VIN.

In 2006 GM changed the way ethanol percentage of fuel was calculated by their trucks.  The new system was called The Virtual Flex Fuel System.  Instead of using an additional sensor in order to measure ethanol content, the ECM had a software upgrade which allowed it to make this measurement by utilizing the fuel tank pressure sensor and level sensor signals.  When the key is turned on the ECM looks to see if the fuel tank level sensor signals at least a 2 gallon change from the last key off.  If the sensor picks up a 2 gallon change, the ECM shuts the tank vent solenoid, monitors the fuel level and fuel tank pressure.  These readings are applied to a formula which gives an ethanol percentage.  The commanded air/fuel ratio is then changed according to ethanol percentage of the fuel.

In 2006, GM trucks used the same 160 pin ECM with blue and green terminal position assurances as did the 2002-2005 trucks.  Aftermarket injection wiring harnesses designed for this ECM and use the factory accelerator pedal and TAC module from the transplant vehicle.

Truck Engines and Throttle by Wire

GM’s V8 throttle by wire lineup consisted of  2000-2002 Gen 3 truck engines and 2003-2006 Gen 3 truck engines with either the 4L60E or 4L80E transmissions. The difference between earlier throttle by wire and the later version is because of a throttle body design change for the Gen 3 truck engines.  Engines built in 2002 or earlier came with a throttle body much like the LS1 in the Corvette.  These throttle bodies are easily identified by the black TAC motor on the passenger side of the throttle body and the TPS opposite to it.  2003 and later throttle bodies have the TAC motor and TPS both on the passenger side.

Aftermarket fuel injection wiring harnesses can be purchased to adapt these throttle by wire systems to work in your transplant vehicle or you can swap out to a throttle by cable type throttle body. The most popular throttle body conversions include the LS1 or LS6 throttle by cable throttle body.

“For a junkyard build,” Golen says, “it’s easier and cheaper to stay with the F-body type cable setup. You can make the throttle by wire system work, but it will require more expense and effort.”

Throttle by wire (Left) and throttle by cable (Right) throttle bodies are identified by an electrical actuator or cable quadrant on the side of the unit.

Cylinder Heads and Casting Numbers

Briggs told us that “The 317 casting number truck head is pretty hard to beat. It’s actually a pretty good head when it comes to boost because of the bigger combustion chamber.”  We checked the 317 casting number flow numbers out and found that they are pretty much the same flow as the LS6 heads. For a budget friendly junkyard build, these heads are a pretty good deal, but only if you are planning on using a power adder like a turbo or supercharger.

An LS6 style head is good for naturally aspirated applications because of the smaller combustion chamber. L92 cylinder heads have become very popular additions to the LQ4/LQ9 iron truck blocks because of their flow. The L92 heads have proven themselves to be rockets based on the racing influenced design of the heads which have raised runner floor and wider port opening by virtue of an offset intake pushrod. Golen believes that “it’s worth the time and effort to find a set of L92 heads for your cast iron block. There are big horsepower gains that can be made with that combination.”

Here’s a quick rundown on the LS cylinder heads by casting numbers:

Casting Number 12564241 or 12559853

  • 1997-2003 LS1 Passenger Cars
  • Aluminum
  • Combustion Chamber Volume: 66.67cc
  • Compression Ratio: 10.1:1
  • Intake Port Volume: 200cc
  • Exhaust Port Volume: 70cc
  • Intake Valve: 2.00”
  • Exhaust Valve: 1.55”
  • Part #12559853 (1997-2000), 12564241 (2001-2003)

Casting Number 12564243

  • 2001 LS6 Passenger Car
  • Aluminum
  • Combustion Chamber Volume: 64.45cc
  • Compression Ratio: 10.5:1
  • Intake Port Volume: 210cc
  • Exhaust Port Volume: 75cc
  • Intake Valve: 2.00”
  • Exhaust Valve: 1.55”
  • Part #12564243

Casting Number 12562317 or 12572035

  • 2001-2004 LQ4/LQ9 equipped truck
  • Material: Aluminimum
  • Combustion Chamber Volume: 71.06cc
  • Compression Ratio: 10:1
  • Intake Port Volume: 210cc
  • Exhaust Port Volume: 75cc
  • Intake Valve: 2.00 inches
  • Exhaust Valve: 1.55 inches
  • Part Number: 12572035

Casting Number 12561873

  • 1999-2000 LQ4 equipped truck
  • Material: Cast Iron
  • Combustion Chamber Volume: 71.06cc
  • Compression Ratio: 9.5:1
  • Intake Port Volume: 210cc
  • Exhaust Port Volume: 75cc
  • Intake Valve: 2.00 inches
  • Exhaust Valve: 1.55 inches

Casting Number 12561706 or 12559852

  • 1999-2004 LR4 equipped truck
  • Material: Aluminum
  • Combustion Chamber Volume: 61.15cc
  • Compression Ratio: 9.5:1
  • Intake Port Volume: 200cc
  • Exhaust Port Volume: 70cc
  • Intake Valve Diameter: 1.89 inches
  • Exhaust Valve Diameter: 1.55 inches
  • Part Number: 12559852, 12561706

Casting Number 12558806 or 933

  • 1997-1998 LS1 (Perimeter Bolt) Passenger Car and Corvette
  • Material: Aluminum
  • Combustion Chamber Volume: 66.67cc
  • Intake Port Volume: 200cc
  • Exhaust Port Volume: 70cc
  • Intake Valve Diameter: 2.00 inches
  • Exhaust Valve Diameter: 1.55 inches

Casting Number 2716 and 5364

  • 2008+ LS3/L92 Passenger cars and Corvette
  • Material: Aluminum
  • Combustion Chamber Volume:68.4cc
  • Intake Port Volume:257cc
  • Exhaust Port Volume:86cc
  • Intake Valve Diameter:2.165 inches
  • Exhaust Valve Diameter:1.59 inches

LS7 Intake manifold with fuel rails.

Intake Manifold

When it comes to the subject of getting air to your engine, Briggs says that there are limitations on stock piece. The factory LS6 intake is pretty decent, as is the LS3 and LS7. But when it comes to truly making power, it make more sense to put a carb’d style intake on or a FAST unit.

“The truck engine intake flows a lot of air but it’s also the tallest. If there is a concern over space issues and the intake fitting under the hood, then you’re going to be forced to use the lower profile intake. The Z06 style manifold is the better one of the car intakes.”  Briggs also explained that the intake off of an F-body Camaro (LS1) would bolt to the truck blocks and work well when space was at a premium.

Golen would opt to stay with the LS1/LS3/LS7 F-body intake “for cost and ease of making the fuel system work properly. The F-body intake includes fuel rails that are a returnless design. Less cost, less plumbing and less work.”

 

GM LS9 Crankshaft

Crankshafts

There’s no need to worry about the quality of a stock crankshaft with a turbo or reasonable horsepower supercharger engine, according to Briggs. “The stock crank is fine. I’ve made over 1,000 horsepower with a stock crank. It’s not the ideal situation and not something that I would not plan on doing routinely but it proves that the stock crank can handle more than the stock cranks of the 70’s or 80’s.”

There are some issues to be aware of however. The 1999 & 2000 LQ4 engine came stock with a 0.44″ longer crankshaft to accommodate the 4l80E transmission engine/tranny combination that was offered in the stock vehicles during that period. The early LQ4 blocks can run the older SBC style transmissions like the TH350, 700R4 and TH400 with no problem. If you want a newer LQ4 block to run an old style transmission, you have to install an older style crankshaft into the block or use a crank spacer for the flex plate.” Golen echoed Briggs by saying, “The stock crank is worth keeping unless you want to push the engine. Then it’s worth it to upgrade to an aftermarket piece.”

Rods & Pistons

Factory pistons are definitely the weak point of the LS family. Assuming you’re looking at a non-LSA/LS9 engine, you’re looking at hypereutectic pistons that won’t survive under high horsepower or boost. However, at the 500-600 horsepower level, they will do for budget builds. The LS7 piston and LS3 piston is a little more stout than the truck or LS1/LS2 units; so you might be able to push things a little bit. However, inexpensive pistons are cheap enough that if you’re scouring the junkyard for pistons you are probably penny-wise and pound-foolish. Same thing with rods, if you’re looking for pistons or rods, for the most part, inexpensive aftermarket offerings are inexpensive and strong.

In Conclusion

We believe that the LS is more than the small block Chevy of this generation. Engine parts are as plentiful and they are clearly better than small block Chevy parts. So we’re talking better design and technology, equal availability, and more durability. We hope this guide helps you identify and pick the best LS parts that your money can buy, and whether you’re surfing a junkyard, Craiglist, or trying to sweet talk your buds into hooking you up – now you know what you need!