The LS7’s racing roots are evident in the cylinder block and reciprocating assembly, where an all-new aluminum block casting accommodates large, 104.8-mm-diameter (4.125-inch) cylinder bores. Aluminum flat-top pistons produce an 11.0:1 compression ratio. Lightweight titanium connecting rods link the pistons to a precision-balanced forged steel crankshaft with a 101.6-mm (4-inch) stroke. The titanium rods weigh just 480 grams apiece – almost 30 percent less than comparable steel rods.
Both the production LS7 and the C6.R race engines use dry-sump oiling systems designed to keep the engines properly lubricated during high-speed cornering. In the production Corvette Z06, an 8-quart reservoir delivers oil to the engine oil pump under the demanding conditions of cornering loads in excess of 1g.
The LS7’s CNC-ported aluminum cylinder heads ensure optimum airflow, the LS7 has straight, tunnel-like intake runners. Large by production-vehicle standards, the ports are designed to maintain high airflow velocity, providing excellent torque at low rpm and fat horsepower at high rpm.
The cylinder heads feature 70cc combustion chambers fed by 56mm titanium intake valves that weigh 21 grams less than the stainless steel valves used in the standard Corvette LS2 small-block V-8, despite the valve head having 22 percent more area. They are complemented by 41mm sodium-filled exhaust valves (vs. 39.4 valves in the LS2). To accommodate the large valve face diameters, the heads’ valve seats are siamesed. Drawing on the experience of Corvette Racing, the LS7’s valve angles are 12 degrees–versus 15 degrees for the LS2–to enhance airflow.
Both the street and competition engines have evenly spaced, symmetrical intake and exhaust ports. Complete CNC porting of the LS7 and C6.R cylinder head is performed on five-axis milling machines, which carve out the intake ports, exhaust ports and combustion chambers with mathematical precision. Airflow through the LS7's cylinder head ports was improved 43 percent on the intake side and 26 percent on the exhaust side over the LS2.
Said Mark Kent: “It was Zora Arkus-Duntov’s vision that Corvette should lead the way with race-ready parts and designs. I think he would be proud of what the GM small-block V-8 has achieved.”