With 500-hp Ford Mustangs and 600-hp Dodge Vipers skulking in the neighborhood, Chevrolet had to do something for the Corvette. That something, for all Corvettes save the Z06, is a power and torque injection for 2008 that comes courtesy of a new V-8.
After only three years of faithful service, the 400-hp LS2 V-8 has been replaced with a nearly all-new LS3 engine that produces 430 hp in standard trim and 436 hp with optional muffler-bypass valves.
The list of redesigned parts runs long: block, crankshaft, pistons, heads, camshaft, valves, and intake rocker arms. Boring out eight big holes an additional 2.15 mm (0.085 inch) adds 0.2 liter of displacement and more bang from every power stroke. The valves, intake and exhaust ports, intake lift, and fuel injector capacity are all larger to raise peak torque from 400 lb-ft to 424 lb-ft at 4600 rpm. The optional exhaust kicks in another 4 lb-ft of torque.
To sustain these upgrades, there are tougher connecting rod bolts and a different machining operation at the bottom of the cylinder bores. Less camshaft overlap allows the LS3 to meet tighter emissions standards. More effective top-cover insulation helps curb valvetrain noise.
The effort invested in the LS3 also will benefit the next new V-8 in the pipeline: the supercharged and intercooled 650-hp blunderbuss due next year for the Corvette SS. The much higher combustion pressures that are created by supercharging necessitate the use of the LS3, with its more substantial cylinder walls, rather than the Z06's 7.0-liter LS7 as the basis of that engine. The blower on top will more than make up for the smaller displacement. Although not yet confirmed, count on the Corvette SS V-8 to take yet another new LS designation: LS9.