Subscribe to the Free

GM Performance Parts LS Engine - Diy LSX 427

Super Chevy'S Guide To Building A 550-Horse Ls Engine From The Gm Performance Parts Catalog.

Barry Kluczyk Jan 1, 2008
Sucp_0801_02_z Gm_performance_parts_ls_engine Completed_block 2/27

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.

Sucp_0801_04_z Gm_performance_parts_ls_engine Crankshaft 3/27

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.

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.

Sucp_0801_05_z Gm_performance_parts_ls_engine Iron_block 4/27

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 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 and on

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.


Chevrolet Performance Parts
Detroit, MI 48232
Thomson Automotive
Wixom, MI



Connect With Us

Get Latest News and Articles. Newsletter Sign Up

sponsored links

subscribe to the magazine

get digital get print