In 2013, a revelation of sorts took place within the Corvette world. General Motors unveiled a “best of both worlds” type offering, which paired the C6 Corvette, in its convertible form, with an indisputably fearsome powerplant. Beneath the Corvette’s hood, sat a 427 cubic-inch small-block, which carried the LS7 designation. Consumers could now cruise about in grandeur while powering down the highway with unabashed tenacity.
The LS7 was notable from many angles, perhaps most indisputable in regards to its technical superiority, when compared to other powerplants of the era. This famed small-block was more than just well-designed. To many, the LS7 is considered an outright engineering marvel.
2013 LS7 (427CI) History
Throughout the decades, GM has made quite the habit out of keeping things interesting toward the end of each of the Corvette’s successive generational production runs. This was a trend that would continue, without question, prior to the C6 Corvette’s farewell.
Those at the helm of the Corvette design must have decided that the only thing better than going fast, was looking good while doing so. Therefore, the decision was made to equip a convertible variant of the C6, with a powerplant powerful enough to stomp out the doubt of any naysayers.
In the name of simplicity, the decision was made to utilize the manufacturer’s already existing LS7 small-block, to fulfill this need. The LS7 had previously found a home beneath the C6 Z06’s hood, where it had staked outright dominance, both on the street and track.
In fact, the LS7-equipped convertible would feature much of the same standard equipment, as that found on the prior Z06, including upgraded steering and suspension components. In total, the 2013 C6 Corvette offered a broad-stroke approach to satisfying the wants and desires of consumers the world over.
With 505 horsepower and 470 lb.-ft. of torque on tap, one would be hard-pressed to paint the 2013 C6 in a critical light, especially in terms of performance. From one end of the spectrum to the other, the C6’s farewell tour was a sight to be seen.
2013 LS7 (427CI) Specifications and Technical Configurations
The LS7 featured a cast block, which included pressed-in cast cylinder liners, which measured 4.125” in diameter. This block housed a forged-steel crankshaft that was held in place via a set of six-bolt, cross-drilled main bearing caps. These caps were designed to reduce crankshaft flex and balance.
Attached to the LS7’s crankshaft, was a set of lightweight titanium connecting rods. These connecting rods were engineered to minimize friction with the engine’s crankshaft and to accept the use of specialty bearings, which were intended to minimize heat build-up.
A set of cast hypereutectic pistons was affixed at the opposing end of the LS7’s connecting rods, via tapered wrist pins. These pistons featured polymer-coated skirts, and anodized rings, which effectively reduced friction, prevented blowby, and suppressed engine noise.
One of the most strategically devised features of the LS7’s construction was the addition of free-flowing cast aluminum cylinder heads. During the development of the LS7’s cylinder heads, data collected by the Corvette race team was utilized, in order to provide an eventual template for production. These heads also featured fully CNC-machined intake and exhaust ports.
Within the LS7’s heads, resided a set of high-flow valves, which measured 2.205” (intake) and 1.610” (exhaust) in diameter. These valves were actuated by a high-performance camshaft, which featured lift values of 0.593” (intake) and 0.589” exhaust.
The LS7’s high-flow composite intake manifold was designed to complement the free-flowing nature of the small-block’s cylinder heads. This manifold was manufactured to minimize runner-to-runner restrictions, thereby enhancing intake efficiency. An insulative layer of acoustic foam was also placed between the top of the LS7’s intake, and its overlying “Skull Cap”, in a bid to reduce vibration.
To better cope with the demands of high-rpm operation, and extensive cornering, the LS7 was outfitted with a dry-sump oiling system. This system prevented oil starvation, in the face of demanding operation, which had become an issue of concern within earlier high-performance GM engines.
All things considered, the LS7-equipped C6 Convertible boasted a top speed of 198 MPH and was capable of completing a ¼ mile pull in 11.8 seconds. The C6 Convertible also recorded 0-60 MPH times of just under four seconds.
LS7 Specs Index
Horsepower: 505 hp @ 6,300 rpm
Torque: 470 lb.-ft @ 4,800 rpm
Compression Ratio: 11.0:1
Displacement: 427CI (7.0L)
Cylinder Bore: 4.125” (104.8mm)
Stroke: 4.00” (101.6 mm)
LS7 (427CI) V8 Additional Uses
The LS7 would continue powering the C6 Corvette until the eventual unveiling of the C7 in 2014. Though rather short-lived, in relation to many other GM small-blocks, the LS7 served its purpose, to a high degree of accuracy. Outside of its use beneath the hood of the 2011-2013 Corvette Z06 Coupe, and 2013 C6 Convertible, the LS7 also powered the Z/28 Camaro from 2014 to 2015.
The LS7 is still offered in the form of an available crate engine, directly from General Motors, and serves as a popular option for those performing engine swaps, in the pursuit of additional power.
The Bar By Which All Others Are Judged
The 2013 C6 Convertible offered consumers more than they could have ever asked for, by completely reimagining what a convertible could, and should be. This sporty creation was equal parts style and performance, making it nearly impossible to remove the grin from the face of those behind the wheel.
At the heart of the C6 Convertible, lies the LS7, which is as revered today, as it was upon the day of its release. The LS7 packed enough of a punch, that few possessed the fortitude to push the famed small-block to its extremes. For all intents and purposes, it is hard to imagine any better powerplant to motivate the sixth-generation convertible variant, of the true American sports car.