1997 Chevy Corvette C5

First Test - #1White-haired John Lingenfelter resembles a blend of the blocky muscularity of a younger Marlon Brando and the marshal steeliness of an Erwin Rommel, Germany's genius general, AKA "The Desert Fox." Appearance aside, this man is internationally recognized as one of the premier Corvette-tuning experts, made most famous by his lightning-quick 475-horsepower ZR-1s.

At his shop in pancake-flat Decatur, Indiana, he seemed to us farm-boy quiet, nearly reluctant to speak, and certainly not given to rambling hyperbole. His incredibly fast cars do the talking. But before we took to the track, we extracted a few words on his latest creation, a 450-horse version of the all-aluminum LS1 tucked into a new C5 Corvette.

"Well, it turned a two-way average of 190 mph," he noted. "But then, it's got a bit more axle than the old car. Actually, we're making more power than the old car's 383, that's at least 450 horsepower. And our best 383 with a 3.42 axle would turn a 12.20 at 119 on 17-inch tires. The C5 has 18-inch rear tires and a 3.42 in the rear. But I'm willing to predict we'll go at least 12.40 and 118 or 119 in the quarter." Not surprisingly, Lingenfelter's estimate was slightly conservative.

Lingenfelter Performance Engineering's reputation is built upon a ceaseless stream of megapower small-block V-8s, infinite displacement and detail variations on a basic Chevrolet engine design that originally debuted in 1955. But love it as America does, it's an engine marked for death at about the time of its 45th birthday. No mourning is necessary because we already know its replacement: the LS1 V-8 architecture introduced in the '97 C5 Corvette. For Lingenfelter, maintaining the company's leading-edge reputation meant being at the forefront in modifying the LS1. The first fruit of that development sits in the nose of the Corvette on these pages: an LS1 swelled from 347 cubic inches (5.7 liters) to 370 (6.1 liters) and bulging with 450 savage horsepower.

The magnitude of the change from the traditional small-block design to the LS1 is apparent in the number of parts that carry over from the older engine to the new. "Well, the rod bearings and hydraulic tappets are the same," explains Lingenfelter. "That's it." The old V-8 was designed using English units of measure, and the new one is altogether metric, so this by itself would have guaranteed virtually total component incompatibility. But the LS1 is more than an old small-block gussied up in metric threads.

In general layout the LS1 remains a pushrod V-8 with a single camshaft in its block operating just one intake and one exhaust valve per cylinder by pushrods and rockers-stone simple in design, but every detail has been massaged. For instance, like the old engine, the LS1 cylinder bore centers are 4.4 inches apart, but unlike the old engine's "siamese" exhaust ports wherein each followed its own eccentric path out of the engine, the LS1's intake and exhaust ports are equidistantly spaced and shaped identically to one another. For engineers, that means the LS1's thermal characteristics are more consistent cylinder-to-cylinder and therefore more manageable for both emissions and performance tuning. And the straight paths that the intake charge and exhaust gases flow through the cylinder heads are inherently more efficient than the angled routes of the old design.

The supple LS1 is overstuffed with details from an elegantly simple valvetrain geometry to an individual ignition coil for each cylinder and lightweight composite intake manifold. But for Lingenfelter, the single most important element of the engine's design is the block's all-aluminum construction.

"The only thing that is negative for us is that the pressed-in cylinder sleeves are thin," explains Lingenfelter. "We can overbore them only about 0.010 inch, where on the old iron engine we could push it out 0.060 inch. All we can do now is stroke." Being limited to stroke, however, doesn't really hamper the maestro all that much.