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