GM used lessons learned from the C5R racing program to develop the 7.0L (427 cubic inches) 505 horsepower LS7 engine, the most powerfull small-block engine GM has ever produced.. The LS7, which is standard equipment in the C6 Corvette Z06, takes Corvette performance to an unprecedented level while demonstrating the continuing adaptability of pushrod/cam-in-block technology.

Unlike the previous Corvette Z06 engine, the LS7 has a separate and distinct engine block casting and reciprocating assembly than the base Corvette engine. The unique block accommodates large-displacement cylinders, while other components make use of racing-derived lightweight components to help boost horsepower and rpm capability.

The 7.0L LS7 Engine

The LS7's competition-proven construction is exemplified in the cylinder block and reciprocating assembly, where an all-new aluminum block casting is used to provide room for its large, 104.8-mm-diameter (4.125-inch) cylinder bores. Inside the cylinders, aluminum flat-top pistons deliver an 11.0:1 compression ratio. They're connected to a precision-balanced forged steel crankshaft with a 101.6-mm (4-inch) stroke via lightweight titanium connecting rods.

Other details of the cylinder block assembly include pressed-in cylinder sleeves and forged steel main bearing caps. Pressed-in cylinder sleeves are used to allow the large 104.8-mm bore while the six-bolt, doweled-in-place CNC-machined forged steel main caps offer the superior strength required at the LS7's power level. The smaller-displacement LS2 engine (101.6-mm bore x 92-mm stroke) has cast-in cylinder sleeves and powder metal main caps.

The C6 Z06 Corvette

The LS7, each of which are hand assembled at GM's Performance Build Center, has a dry-sump oiling system and air-to-air oil cooler, designed to keep the engine properly lubricated during the high cornering loads the Corvette Z06 is capable of producing.

The LS7's CNC-ported aluminum cylinder heads are all-new and designed to meet the high airflow demands of the engine's 7.0-liter displacement. Airflow has increased 25 percent compared to the base Corvette's 6.0-liter LS2 engine. The heads feature 70-cc combustion chambers that are fed by 56-mm titanium intake valves. They are complemented by 41-mm sodium-filled exhaust valves. The LS7's valve angles are held at 12 degrees - vs. 15 degrees for the LS2 - to enhance airflow through the ports. Complete CNC porting of each cylinder head is performed on state-of-the-art five-axis milling machines.

Based on C5R racing experience, the LS7's cam has an all-new profile that provides .591-inch lift (15 mm) on both the intake and exhaust valves - almost .066 inch more than the LS2's already stout .525-inch lift specs.

Like other Gen IV engines, the LS7 uses a composite intake manifold, although its passages are tuned to support the LS7's greater airflow requirements. The manifold is fronted by a 90-mm-diameter electronically controlled throttle body. High capacity, five g/sec fuel injectors also are mounted in the manifold assembly. On the exhaust side, racing-style tubular steel headers are used. The individual header tubes meet at a special quad-outlet collector flange at the very tip of the header outlet where they smoothly enter into a "wide-mouth" catalytic converter.