GM Performance Parts LS Engine - Super Chevy Magazine

Gm Performance Parts Ls Engine Completed Block

Crate engines, crate engines, crate engines. Who doesn't love crate engines? For many enthusiasts, a carefully selected crate engine is the best way to power-up a project car. But there are still a few out there who actually enjoy building their own engine. it comes from the satisfaction of doing something yourself and, yes, the ego rush that occurs when replying to a question about the engine builder and replying, "Me!"

And while thousands of traditional small-blocks and rat engines are built at home each year, not too many enthusiasts have tried their hand at building a high-performance, late-model LS engine. As it turns out, the assembly process is easier than building any old-school Bow Tie engine. For one thing, the LS uses all dry seals and only a few different socket sizes are needed.

Gm Performance Parts Ls Engine Crankshaft

An ls7 forged steel crankshaft, part number 12568820, came next. it delivers a 4.000-inch stroke which, combined with the 4.125-inch bores, gives the engine its 427-cubicinch displacement.

An ls7 forged steel crankshaft, part number 12568820, came next. it delivers a 4.000-inch

We recently participated in an LS build that used GM Performance Parts' (GMPP) newer LSX ironcylinder block as the foundation. Its sub-$2,000 price makes the block affordable and, because it was designed to accommodate the performance whims of racers trying to push 30 pounds of boost (or more) through its walls, it's plenty durable for just about any street combination you could think of.

The project engine combined the LSX block-machined to 427 cubic inches-and a raft of LS7 parts, including the racing-derived, high- flow aluminum heads, intake manifold, camshaft and more. The 427-inch displacement enabled the use of GM's newly available LS7 controller, which allowed the engine to start up on the dyno with no separate tuning. The controller was simply plugged into the engine's wiring harness and-Vroom!-the engine was idling smoothly from the first push of the starter button.

Gm Performance Parts Ls Engine Iron Block

The starting point for the project was the lsx iron cylinder block, part number 19166454, which can be had in most places for less than $2,000. it is based on the Gen iV "ls" engine design, but with provisions for six-bolt cylinder heads. The Chevy-orange paint is standard, too.

The starting point for the project was the lsx iron cylinder block, part number 19166454,

The engine combination, which also included all-forged reciprocating parts from the GMPP catalog, produced 550 hp and 511 lb-ft of torque on the engine dyno at Detroit-area Thomson Automotive. Most surprising, however, was the ease at which the engine got up and running. By using the GMPP controller, which was preprogrammed with the maps to sustain the 427-inch engine, there was little to do between start-up and the dyno pulls besides let the engine oil come up to temperature. No timing adjustments, fuel adjustments or other tuning was required. It was almost too easy.

Our involvement with the project coincided with a video production that GM Performance Parts was shooting to highlight the LSX's performance potential. Nate Pritchett, from SPEED's "Pinks" show was on hand and GM's Thom Bates did most of the wrenching. Thomson Automotive supplied the facilities, some expert guidance and lunch-along with the dyno.

You can see a video showing highlights of the buildup on gmperformanceparts.com and on youtube.com.

If you're wondering about a ballpark price for the engine we built, it is roughly $12,000. And unless you've got a machine shop in your backyard, you'll need to tack on a few hundred bucks for the finish work on the block. Still, given the power output of this mill, the word "value" is not out of place when describing it.

For now, follow the photos to see what it took to build our 550-horse LS engine.

The LSX block is delivered in semi-finished form, meaning it must visit the local machine shop for finish work before the engine buildup starts. Ours was taken to Thomson Automotive, where the bores were finished to 4.125 inches with torque plates clamped to the decks.
The LSX block is delivered in semi-finished form, meaning it must visit the local machine
When it came time to start assembling the engine, the wrench turning was handled by GM Performance Parts' Thom Bates, who started by inserting the camshaft. We used an ls7 cam, part number 12571251, which has 0.591-inch lift on both sides and 211/230 duration specs.
When it came time to start assembling the engine, the wrench turning was handled by GM Per
One of the assembly details new ls engine builders will have to get used to is torque-to-yield fasteners. These are one-time-use bolts that, in addition to a traditional torque wrench, also require a torque-angle meter to achieve the correct final torque spec.
One of the assembly details new ls engine builders will have to get used to is torque-to-y

One of the toughest jobs of an ls engine assembly is installing the damper, part number 12576652, which is a super-tight fit. We used a tool designed by Thomson Automotive. GM also has a tool for the procedure.
One of the toughest jobs of an ls engine assembly is installing the damper, part number 12
With the rods and pistons assembled, they were ceremoniously dropped into the cylinder block.
With the rods and pistons assembled, they were ceremoniously dropped into the cylinder blo
With the rods secured, the windage tray was set in place, but we didn't simply torque it down and move on to the next assembly step.
With the rods secured, the windage tray was set in place, but we didn't simply torque it d

The solution to the rod/windage tray interference problem is adding washers to the attachment studs to serve as spacers. it's all that is necessary to provide adequate clearance.
The solution to the rod/windage tray interference problem is adding washers to the attachm
Next up was the assembly of the rods and pistons. We used the cast ls7 pistons, part number 89018171, and exotic, super lightweight forged titanium ls7 rods, part number 12586258. With our 70cc cylinder heads, compression checks in at 11.0:1-perfect for a modern 93-octane street mill.
Next up was the assembly of the rods and pistons. We used the cast ls7 pistons, part numbe
Like so many other fasteners on the engine, the rod bolts are torque-to-yield. GMPP's Thom Bates snugged them down and checked the clearance between them all.
Like so many other fasteners on the engine, the rod bolts are torque-to-yield. GMPP's Thom

On LS engines with more than a 4.000-inch, or greater, stroke, the rod ends will likely interfere with the windage tray. Bates checked this by carefully rotating the crankshaft and noting whether the rods hit the tray. They did.
On LS engines with more than a 4.000-inch, or greater, stroke, the rod ends will likely in
The oil pump pickup was next. Because the engine can't be primed via a distributor hole like classic small- and big-block engines, it's important to get some oil into the pickup at this stage of the build.
The oil pump pickup was next. Because the engine can't be primed via a distributor hole li
We installed an F-car oil pan, part number 12558762, as it's the most "universal" of the various ls-engine production pans. in other words, it's the one that will retrofit into an older car with the least amount of hassle.
We installed an F-car oil pan, part number 12558762, as it's the most "universal" of the v

With the short-block assembled, the heads came next. Here, Bates drops on one of the ls7 aluminum heads.
With the short-block assembled, the heads came next. Here, Bates drops on one of the ls7 a
We used GM's ls-series lifter kit, part number 12499225, which includes 16 hydraulic roller lifters. They were doused in oil prior to installation.
We used GM's ls-series lifter kit, part number 12499225, which includes 16 hydraulic rolle
One of the unique features of the ls7 heads is offset intake valves, which necessitates correspondingly offset rocker arms, one of which is shown being installed here. Both the intake and exhaust ratios are 1.8:1.
One of the unique features of the ls7 heads is offset intake valves, which necessitates co

One of the most crucial inspections during the assembly is the squaring of the oil pan with the cylinder block. The best way to get it right the first time is running down the oil pan bolts, but leaving them a little loose; then, a straight edge is used to check that the pan and block are square. When everything lines up correctly, the pan bolts are final-tightened.
One of the most crucial inspections during the assembly is the squaring of the oil pan wit
The LS7 heads are masters of airflow. They're CNC-ported at the factory and flow approximately 350 cfm through 270cc intake ports. The intake valves are titanium and are 2.20-inches in diameter, while the 1.61-inch exhaust valves are sodium filled. They're all held at a 12 angle.
The LS7 heads are masters of airflow. They're CNC-ported at the factory and flow approxima
On all other ls engines, the lifters can be dropped in lifter guides that install two at a time. The provisions for extra head bolts on the lsx block, however, make that impossible. so, they're carefully inserted, one at a time, and held in place with lsx-specific guides that come with the cylinder block.
On all other ls engines, the lifters can be dropped in lifter guides that install two at a

Our engine builder, Thom Bates, took credit for pushing through at GMPP the ls7 intake assembly, part number 12568976, coming with the throttle body, fuel injectors and fuel rails pre-installed. it makes topping off the engine a much easier, quicker job.
Our engine builder, Thom Bates, took credit for pushing through at GMPP the ls7 intake ass
Assembly of the engine was wrapped up with the installation of the water pump, part number 89018053.
Assembly of the engine was wrapped up with the installation of the water pump, part number
On the superFlow dyno at Thomson Automotive, our lsx 427 kicked out an impressive 550 hp and 511 lb-ft of torque (sTP correction). This was with no tuning or external adjustment; the ls7 controller was simply plugged in and the engine was run on its preprogrammed tune. We were thrilled with results, as the performance was achieved with off-the-shelf catalog parts and a by-the-numbers assembly. Our engine was fuel-injected and used drive-by-wire electronics. GMPP has the necessary parts if you'd like to go this route. if you're going carbureted, you can use a regular, old throttle cable.
On the superFlow dyno at Thomson Automotive, our lsx 427 kicked out an impressive 550 hp a

Surprisingly, the ls7 coil packs don't come as an assembly, even though that's how they installed on the engine. The individual coils and mounting bracket must be purchased separately.
Surprisingly, the ls7 coil packs don't come as an assembly, even though that's how they in
One of the key enablers to making our engine project a turnkey affair was the use of GMPP's new, stand-alone ls7 controller, part number 19166567. it allowed the engine's wiring harness to simply plug into this ECM and-bingo-the engine was timed and tuned from the get-go. it could not have been easier to get the engine up and running.
One of the key enablers to making our engine project a turnkey affair was the use of GMPP'