Late-model GM Small-Block V8 engines | Buyer's Guide | Articles

Story by Liz Miles

The small-block Chevy has been an immensely popular engine since its 1955 release. While many consider this V8 to be a big, fat iron anchor when compared to today’s imported, all-aluminum inline fours, it was a revolutionary engine for its time.

The original Chevy V8 continued to build power in a reliable package for decades—basically until the turn of this century, when it was finally superseded. In the early ’90s, General Motors assigned their brightest research and development staff members to design a new small-block that could be used across their lineup.

They came up with the first Gen III small-block V8. It was called the LS1. No one could have predicted the popularity this engine would gain after its debut in the 1997 Corvette; by 2001, the Gen III had taken over completely.

What’s so remarkable about this engine? For one, it was built with the aftermarket in mind. GM gave the engine a low profile so it would easily fit in different cars. The engine is also simple to build and upgrade. The LS engine starts with an aluminum six-bolt main block that is far stronger than any early iron block while weighing about 40 pounds less. With this base, GM built a rotating assembly that can easily support 500 horsepower.

Superior cylinder head design allows the LS to make big power with stock and aftermarket parts. The engine was built to be assembled like a Lego set, and each piece fits together with dry gaskets. There are four exceptions: the pea-sized globbies found at each corner of the oil pan gasket.

That first LS was only the beginning. The LS6 came next and featured better-flowing heads, a more radical cam, and a higher-flowing intake manifold for 400 out-of-the-box horsepower.

[Addressing internet myths about LS swaps]

Iron-block versions of the LS6 were put into trucks and SUVs. They offer more room for bigger bores and usually feature a lower compression ratio, a trait that works well with superchargers and turbos. From there, the line exploded into 650-horsepower models as well as ones fitted with variable valve timing and displacement-on-demand features.

There have now been more than two dozen different LS-series engines. Here are the versions that seem to work best with the gearhead set—and can be easily acquired without destroying your budget. These can be purchased new through GM Performance Parts or found at the local salvage yard.

LS1

The original model received 15-degree, cathedral-port heads that flow excellently. Power adders work well with the 10:1 compression ratio.

found in: 1997-2004 Corvette, 1998-2002 Camaro/Firebird, 2004 GTO
displacement/compression: 346 cubic in., 10.1:1
output: 300-350 horsepower, 320-375 lb.-ft.

LS6

Basically an LS1 fitted with even better heads, a bigger cam and a higher-flowing intake manifold. These heads are very impressive for their age.

found in: 2001-’04 Z06, 2004-’05 CTS-V
displacement/compression: 346 cubic in., 10.5:1
output: 385 or 400 horsepower, 385 or 400 lb.-ft.

LQ4/LQ9

Call it the iron-block version of the LS6; it was made for the GM truck and SUV line. It has a 4-inch bore that is compatible with the better L92 and LS7 heads. The heads it comes with are similar to those on the LS6, but with a larger combustion chamber. The LQ9 has more compression and a more aggressive camshaft. Great base for real performance.

found in: 1999-2004 Silverado, Suburban, Yukon, and Hummer H2 (LQ4); 2002-’06 Escalade; 2003-’07 Silverado SS and Sierra (LQ9)
displacement/compression: 364 cubic in., 9.4:1(LQ4), 10.1(LQ9)
output: 300 horsepower, 360 lb.-ft. (LQ4), 345 horsepower, 385 lb.-ft. (LQ9)

Vortec 5300

(LM7 Gen III iron, LM4 and L33 Gen III aluminum, LH6 Gen IV aluminum)

The most plentiful of the Gen III and Gen IV engines, with more than five million cores currently found in North America alone. Choose between the iron- and aluminum-block configurations. Beware: Not all engines named Vortec are Gen III or IV. The one you want is easily identified by a forward-mounted throttle body. The LM4, L33 and LH6 are aluminum-block versions that have 9.5:1 to 9.9:1 compression ratios, meaning power ranges appropriately. The iron LM7 and LY5 have similar compression ratios but feature iron blocks. Avoid the Vortec 4800, though.

found in: 1999-and-up mid- and full-sized trucks and SUVs
displacement/compression: 325 cubic in., 9.5:1 to 9.9:1
output: 280-315 horsepower, 320-338 lb.-ft.

LS2

Time for a Gen IV revision to the popular GM V8. LS6 heads are still used, but with a large 4-inch bore and an LS6 camshaft. Compression ratios are up. This one is just now getting old enough to be found in the yards.

found in: 2005-’07 Corvette, 2005-’06 SSR, 2005-’06 GTO, 2006-’07 CTS-V, 2006-’09 Trailblazer SS
displacement/compression: 364 cubic in./10.9:1
output: 400 horsepower, 400 lb.-ft.

LY6

This is the Gen IV answer to the iron-block LQ4/LQ6 engines. Variable valve timing bumps the output. In a few years, this will be a junkyard score. Iron block plus low compression: Boost, anyone?

found in: 3/4-ton 2007-and-up Silverado, Sierra, Suburban and Yukon
displacement/compression: 364 cubic in., 9.67:1
output: 353 horsepower, 373 lb.-ft.

Making it Fit

Choosing your engine is the easy part. The real challenge is getting the engine to fit and work correctly in in its new home. There are a couple of hurdles that need to be jumped along the way, and your best resource is someone who has done it before. Though we can’t possibly go through every swap vehicle possibility, here are the key areas of concern.

Accessory Drives:

GM offers two basic accessory drive systems that are aimed at the aftermarket. One comes from the Corvette and the other from the Cadillac CTS-V.

All of the dimensions are available on the GM website, but in a nutshell the Corvette accessories fit better in engine bays that are restricted in the lower areas but more open near the top. The CTS-V kits are intended for a more square space where the base of the engine bay has the same amount of room as the top. The fourth-generation F-body has its own drive system, but it isn’t available in an aftermarket kit.

Engine Mounts:

Depending on the car you’re working on, you may have to shop around for engine mounts. Doing an early Z-car swap? A popular bolt-in engine mount kit for the Datsun 240Z comes from JCI. This kit eliminates any guesswork, and transmission mounts are included.

Other popular LS engine recipients are the S13- and S14-chassis Nissan 240SX as well as the 350Z and G35. Sikky Manufacturing has kits for these swaps. If you’re working with a domestic car that uses the traditional early-style mount, Holley has a number of engine mounts for adapting and relocating an LS engine.

Oil Pan:

There’s something about the shape of the LS engine’s oil pan that doesn’t work well with swaps. Fortunately, the aftermarket offers solutions that will clear most crossmembers and also relocate the oil filter.

Holley supplies oil pans for many common LS swap projects, including early Camaros, Chevelles and tri-five Chevys. These cast-aluminum pieces mimic the ones used on the early small-block Chevy. It’s also safe to say that if you’re going from an early small-block to an LS block, you’ll be able to use the Holley oil pan, even if it’s not in a domestic car.

Sometimes the stock pans do work, however. For example, generally a Camaro pan will fit a 240Z.

Transmission:

The LS’s bolt pattern is functionally identical to that of every small- and big-block Chevy ever made. The engine’s cylinder head-to-transmission bolting surface is an inch smaller than that of an early-style engine, however, so a spacer is required to put the flywheel or flexplate into its natural position. If you’re using a transmission built for an LS engine, then of course you won’t need this. Just be sure to pay attention to the pilot bushing, as many cranks have provisions for an outer and inner location.

Exhaust Headers:

Many swap kits include long-tube, mid-length or shorty headers. In a medium-performance application, mid-length headers are a good option because they allow for maximum ground clearance.

Electronics:

The factory harness and fuel-injection system is usually pretty easy to transplant along with the engine, although the aftermarket is ready to help. There are countless manufactures that make replacement or swap harnesses, including Street & Performance, Painless Performance, Summit Racing and GM Performance Parts.

Emissions:

Things start to get hairy, especially in California, when it comes to engine swaps. Yeah, we’re talking about emissions inspections. In time, the whole country may be subject to the same level of scrutiny.

However, GM Performance Parts has created their E-Rod program, a line of completely emissions-compliant crate engine packages. They come with every emissions component needed to run the engine, including the evaporation canister, catalytic converters and exhaust manifolds with oxygen sensors. The correct gas pedal, computer and wiring harness are also included.

Join Free Join our community to easily find more V8, GM, LS6, Buyer's Guide, Engine swap, ls1, vortec, LS, lq4, LS2, LY, Vortec 5300, LQ, LQ9 and LY6 articles.

Comments

siranthony23
7/11/22 1:46 p.m.

quiero hacerle un swap a mi pontiac fiero gt 1986 y deseo saber sobre los motores y accesorios que tengan disponibles

Noddaz GRM+ Memberand UberDork
7/11/22 6:27 p.m.

Bienvenido a bordo!

Si desea mantener todo GM, un motor 3800 sobrealimentado requeriría algo de trabajo pero encajaría.

Pero tu pregunta es para otro hilo. Este hilo es para hablar sobre diferentes motores GM v8.

Si esto te parece una tontería, gracias al Traductor de Google.

Thank you Google Translate

fidelity101 UberDork
9/6/22 1:42 p.m.

sloppy mechanics would argue against avoid the 4800 series.

classicJackets (FS) SuperDork
9/6/22 2:41 p.m.

For the folks who have really done it - how bad is the 1998 LS1 to swap? I see there are kits out there to convert to later PCM for relatively cheap, but it sounds like the remainder of the electrical has other cocnerns too if you were to swap to a later year engine.

I have a 1998 LS1/T56 that would love to swap into something else, and i have access to an LQ9. I would need car accessories regardless.. Would be great to swap the LS1 in, and swap it out for the LQ9 down the road - but hesitant to start if it would require a complete rewire down the road anyway.

Thanks!

A 401 CJ GRM+ Memberand SuperDork
12/18/22 8:37 a.m.

Noddaz said:
Bienvenido a bordo!

Si desea mantener todo GM, un motor 3800 sobrealimentado requeriría algo de trabajo pero encajaría.

Pero tu pregunta es para otro hilo. Este hilo es para hablar sobre diferentes motores GM v8.

Si esto te parece una tontería, gracias al Traductor de Google.

Thank you Google Translate

Well I don't know - maybe you can swap an LS into a Fiero. In the day they made a kit from V8 Archie to fit an old-school SBC. So why not?

A 401 CJ GRM+ Memberand SuperDork
12/18/22 8:41 a.m.

fidelity101 said:
sloppy mechanics would argue against avoid the 4800 series.

So would Richard Holdener.

Pete. (l33t FS) GRM+ Memberand MegaDork
12/18/22 9:25 a.m.

classicJackets (FS) said:
For the folks who have really done it - how bad is the 1998 LS1 to swap? I see there are kits out there to convert to later PCM for relatively cheap, but it sounds like the remainder of the electrical has other cocnerns too if you were to swap to a later year engine.

I have a 1998 LS1/T56 that would love to swap into something else, and i have access to an LQ9. I would need car accessories regardless.. Would be great to swap the LS1 in, and swap it out for the LQ9 down the road - but hesitant to start if it would require a complete rewire down the road anyway.

Thanks!

The computer can't control a 4L80 and you can't get the forced induction operating systems from HP Tuners. The computer is also not pin-compatible with the '99-up one so you will be either doing a lot of repinning, possibly replacing the shells, if you swap to a newer computer. (I forget if the shells are compatible, pinouts are definitely way different)

If you just want to swap an engine, and don't care about swapping in a 4L80 or using one of the custom OSs available from HPT, go for it.

The engine side is 100% compatible with any other 24x engine, which an LQ9 should be. That is the high comp iron block 6.0 from the Escalades, right? Done that swap with the LQ9 harness and a blue/red computer from something or other, which was a 24x setup. The blue/red computer can be swapped into a (blue/green?) harness by trimming the uniquifier tabs off of the different connector. I *think* they are pin compatible but the O2 sensors needed to be rewired because they grounded the sensors differently. Been a while. But I found all the info online at lt1swap.com when I did it. EXTEMELY good resource, there!

SV reX MegaDork
12/18/22 1:34 p.m.

Good article.

Why avoid the 4800? It's an over square design, which means it can rev crazy high. It may not have the torque of it's bigger counterparts, but it seems like a really nice option for a sports car.

What am I missing?

billstewartx Reader
12/18/22 3:01 p.m.