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.
An ls7 forged steel 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.
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.
The starting point for the...
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 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...  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. |  When it came time to start...  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. |  One of the assembly details...  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. |