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LS-7 Power Play

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  • Based on the Gen IV small-block V-8, the LS7 has a unique aluminum cylinder block casting that accommodates the larger, pressed-in liners for the 4.00-inch bores. A 3.62-inch stroke gives the engine its 7.0-liter displacement. - 1
  • The LS7’s cylinder heads look as if they’re meant for a racing engine. They’re CNC-ported hunks of aluminum, with large, straight intake runners. High-performance valves consist of titanium on the intake side and sodium-filled for the exhaust. - 2
  • Flat-top pistons (with valve relief) provide an approximately 11:1 compression ratio. The connecting rods are made from titanium and offer not only weight savings, but also reduced inertia for quicker revving. - 3
  • The LS7’s home is the ’06 Corvette Z06, with weighs approximately 3130 pounds. With the 505-horse engine, the power-to-weight ratio is an enviable 6.20 pounds per horsepower. - 4
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by Barry Kluczyk  More from Author

The Meanest Chevy Small-Block V-8 Ever Created

With 427 cubic inches and 505 hp, the ’06 Corvette Z06’s new LS7 all-aluminum small-block V-8 brings a level of performance to the street that was previous only seen on the racetrack.

Chevy claims that in the roughly 3130-pound special Vette, the LS7 enables 0-60 times in less than 4 seconds, quarter-mile times of less than 12 seconds and a top speed of more than 190 mph.

Unlike the previous Chevy 427 engine, which was a big-block design, the LS7 is based on the Gen IV small-block that lives in other Corvettes (and the SSR roadster) as the LS2, but has a unique cylinder block casting that permits the huge 7.0-liter – 427 cubic inches – displacement. Compared with the LS2, the LS7 also has a different front cover, oil pan, exhaust manifolds and cylinder heads, just to name a few.

Inside, the LS7’s reciprocating assembly uses racing-derived lightweight parts, including titanium connecting rods and intake valves. And to keep the forged crank bathed in oil at all times, even during high-load cornering, the LS7 uses a unique dry-sump oiling system. Dry-sump oiling system

The LS7’s CNC-ported aluminum cylinder heads are an all-new design flow approximately 100 cubic feet more air per minute than the LS2. A hydraulic roller camshaft with approximately 0.590-inch lift matches the heads.

The heads feature 70-cc combustion chambers that are fed by huge, 56-mm-diameter titanium intake valves. The lightweight titanium valves weigh 21 grams less than the stainless steel valves used in the LS2. Sodium-filled 41-mm exhaust valves complement them. And owing to the C5R/C6R racing programs, the valves are held at 12 degrees, versus 15 degrees for the LS2. 

As for the LS7’s dry-sump system, an engine compartment-mounted 8-quart reservoir delivers oil at a constant pressure to a conventional-style oil pump pick-up at the bottom of the engine. The pressurized oil feed keeps the oil pick-up continually immersed in oil at cornering loads exceeding 1 g. Oil circulates through the engine and down to the oil pan, where it is sent back to the reservoir via a scavenge pump.

Every LS7 engine is assembled by hand at GM’s new Performance Build Center in Wixom, Mich. The exacting standards to which they are built include deck-plate honing of the cylinders – a procedure normally associated with the assembly of racing engines and almost unheard of in a production-vehicle engine.

Without a doubt, the LS7 is the high-water mark for small-block development. The good-old days were never this good.

 

LS7 7.0-Liter V-8 at a Glance

Engine type                   OHV V-8, two valves per cylinder; aluminum block and heads

Displacement                427 cu in / 7.0 liters

Horsepower                 505 @ 6300 rpm

Torque (lb.-ft.)             470 @ 4800 rpm

Max. engine speed        7000 rpm

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