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LSX Engine Build - The Future Of Chevy Performance Is Here

The Inside Story On How GMPP Built The World's First LSX-Based Engine

By Dr Jamie Meyer, Photography by Michael Yoksich, Dr Jamie Meyer

The Reggie Jackson '69 Camaro debuted at the 2006 Las Vegas SEMA trade show with all of the subtlety of a 500-foot home run blast. Bright red in color with a slammed, pro-touring stance, the car oozed power, muscle, and performance-some of the same attributes that helped its owner have a Hall of Fame major league baseball career. And, underneath all of those trimmings lies the main reason this car is so special: the first application of GM Performance Parts' new, ground breaking LSX Bow Tie block.

The amazingly efficient 454-inch LSX-blocked engine in Reggie's car cranks out over 640 hp and 610 lb-ft of torque from pump gas. Besides the LSX block, several one-off and hand-fabricated pieces had to fall into place before the ignition could be fired on this new generation Chevy engine. This is the story of how the first LSX engine was designed, assembled, and brought to life by GM Performance Parts.

There is no question that General Motor's LS family of engines has redefined efficiency and performance from a small-block, pushrod V-8. The 400hp factory offerings have been no problem for LS1 LS6 and LS2 configurations, and with the amazing LS7 (as found in the current production ZO6 Corvette-the fastest factory Chevrolet Corvette ever sold to the public) the 500hp plateau has been bridged.

In the aftermarket, serious drag racing, road racing, and street car efforts have taken factory aluminum LS blocks well beyond the 1,000hp level. But that has come with exotic fasteners, very expensive machining procedures, and a borrowed life expectancy.

The aftermarket has countered with some truly impressive pieces. High-end LS blocks like GM Racing's C5R Corvette block have allowed big power LS engines to function flawlessly past 1,000 hp. About the only downside to the aftermarket solution of high-performance aluminum LS blocks is the cost. Often, bare-aluminum "high-end LS" blocks can cost over $5,000. And, while that will certainly work, it goes against the low-buck, high-efficiency design that the LS family of engines has defined for over a decade.

Enter GM Performance Parts. In late 2005, its marketing and engineering staff began the process of designing a better LS block. The goals were simple: Allow big-time, race-car applications for the street or track, while keeping the cost as low as possible. To do this, the team enlisted the help of Warren "The Professor" Johnson, their six-time NHRA Pro Stock drag racing champion, and a man who knows a thing or two about what makes a great race block. Starting with the math data of the 6-bolt main LS7 427-inch block, GM Performance Parts and WJ started tweaking things. First, the decision was made to go with cast iron as a material. This would keep the cost low, the machining costs down, add an incredible amount of strength to the finished project, and allow for a massive bore size for naturally aspirated engine combinations.

In addition, looking into the future use of the LSX block (PN 19166454), one can appreciate that the same block can quite literally grow with the owner as his/her needs expand. If the block were to get wounded in a racing effort, just have it machined/honed for the next-sized piston. No elaborate sleeving of the block would be needed. Additional material has been added to the deck surfaces, main web areas, siamesed bore, and oil pan rail.

For those interested in big nitrous systems, large superchargers, or twin turbocharging, the LSX is the block for you. One of the most groundbreaking features is the six-bolt-per-cylinder design. An additional fifth and sixth head bolt have been added to increase the clamping force of the head onto the block's deck surface so that high compression applications (such as 45-plus psi of boost from a forced induction combination) doesn't literally lift the head off the block. According to GM Performance Parts: "The additional fifth and sixth head bolt holes have been added for boosted and high-compression engines. All six bolts per cylinder are on the same bolt diameter for better gasket sealing and clamping."

Other attributes of the factory LS7 block were left in place such as the bay-to-bay breathing design. This release of crank case pressures from one cylinder to the next was worth over 35 hp in the production 505hp LS7, while costing nothing in structural rigidity. One can only imagine what it will be worth to the 2,000hp engine combinations that are being planned for the LSX Bow Tie block.

In its final form, the LSX offers the potential for a massive 4.25-inch max bore that allows for 482ci from a small-block LSX engine using the max stroke. And, with the forthcoming tall-deck version (9.7-inch deck height), you are looking at 510ci small-blocks.

By Dr Jamie Meyer
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