Photos by Mike Galimi and Courtesy of GM Performance Parts
The Big Three have jumped into the grassroots performance scene in a lot of different ways, while others are dabbling in class-specific racing, the gang at GM Performance Parts (GMPP) tapped their area of expertise of crate engine production for its grassroots efforts. The GMPP catalog has staked its claim as being the leader in crate engine offerings from entry-level small-blocks and four-cylinder power plants to robust 572-ci street monsters. The company even offers a spec-engine for various circle track racing sanctions. Amongst the small and large crate engines sits its highly acclaimed LS lineup that includes green offerings (E-Rod emission-compliant packages), production-style engines, short-blocks and a stout 454-ci LSX pump gas engine. But the LS story doesn’t end with its monster LSX 454; GMPP is releasing its most powerful crate engine to date, and it’s targeting the grassroots drag racing segment. Please give a warm welcome to the GMPP LSX 454-R crate engine and all of its 720 hp.
GMPP rolled out its LSX program in 2007, and the major marketing force was on the drag strip where the company got involved with the NMCA LSX Shootout and backed several other drag racing efforts. The LSX block was an instant hit and is now a cornerstone in the world of big horsepower on the street and strip. Its popularity is no surprise since the factory speed shop worked with NHRA Pro Stock legend Warren Johnson to design a block capable of supporting 2,000-plus horsepower while remaining applicable to street-only engine builds. The new LSX 454-R crate engine is merely building on the high-performance platform that was rolled out almost four years ago.
The LSX 454-R engine is not just a poked and stroked bullet that was bolted together and rushed to market. There were several LSX racers who helped contribute data and feedback on various combinations as well as a full-bore engineering effort inside of GM to produce the 720 hp. The highlights of the engine include the brand-new LSX DR head and intake components, but it all starts with the LSX block foundation. The six-bolt main, cast-iron block has its bores enlarged to 4.185 inches each in diameter, while the stroke checks in to the party at 4.125 inches. The forged pistons are connected to the stroker crankshaft via 6-inch-long 4340 I-beam connecting rods.
Moving topside, the main ingredients include the brand-new LSX DR cylinder heads and intake manifold. The LSX-DR heads come standard on this engine and feature CNC-porting, 11-degree valve angle and six-bolts per cylinder that are designed to be used with the LSX block. The heads are capable of serious flow numbers, and the CNC-ported intake runners push 435 cfm at .800-inch lift, while using a 2.25-inch stainless steel valve, 4.185-inch bore and 28 inches of water on the test stand. Moving to the exhaust ports shows GMPP’s handiwork on the CNC mill nets a port flow of 252 cfm at .800-inch lift, 1.625-inch stainless steel valves and same flow-bench criteria as the intake test. For those interested in the intake port volume, GMPP lists it as 316cc and the combustion chamber is 50cc.
The in-block camshaft bumps the valves a maximum of 0.738-inch, both intake and exhaust. The rest of the cam specs include 250 degrees of duration on the intake side and 270 degrees for the exhaust (measured at 0.050-inch lift), with a lobe separation angle of 108 degrees. Mechanical roller tie-bar lifters are installed to transfer the lift to the pushrods and ultimately to a set of shaft-mounted 1.9:1 ratio roller rocker arms. Topping the induction system is the LSX-DR intake manifold designed to work on top of the heads bearing the same moniker. It accepts a 4500-style carburetor and has extra material for professional porting. GMPP tops the engine with a Holley 4500 carburetor, otherwise known as a Dominator, and it flows 1,150 cfm.
All told, the 454ci powerhouse cranks out 720 hp at 6,800 rpm, while torque peaks at 630 lb-ft. GMPP suggests 110-octane as the minimum and max rpm is 7,100. Based on quarter-mile calculations, that type of power should push a 3,200-pound vehicle into the low 10s/high nines with speeds over 135 mph. The engine is available at any one of the 4,500 GM dealers (140 are authorized GMPP sales centers), and it’s only a few clicks away online at the division’s website.
GM Performance Parts
www.gmperformanceparts.com (http://www NULL.gmperformanceparts NULL.com)