Top speed is one of those irrational yardsticks by which we judge cars. In the early ’90s, cracking the 200-mile-per-hour barrier was the big goal. The Lamborghini Diablo was one of the first to do it in 1990 with a top speed of 202 mph, followed closely by the Ferrari F40, which could go 201 mph. Then came vehicles such as the Bugatti EB110 and the Jaguar XJ220, which both managed an impressive 212 mph. Yes, the early ’90s were full of competing supercars trying to nab the crown, all of which were quickly humbled by the McLaren F1, which posted a seemingly untouchable 231-mph top speed.
But what if we told you that a few years before any of these supercars hit the street, there was a Corvette you could buy that would go 255 mph? Well, it’s true, and the car’s name was the Callaway Corvette Sledgehammer. Based on a C4 Corvette, the Sledgehammer was heavily modified to achieve such speeds with a NASCAR-based, twin-turbo V8 engine and a body kit that looked as slick as it slid through the air. The car’s record-breaking top-speed run occurred on October 26th, 1988, years before the class of supercars from the early ’90s and decades before the Bugatti Veyron would come close to matching it.
What Went Into Making The Sledgehammer
The heart of the Callaway Corvette Sledgehammer is its engine: a NASCAR-spec crate motor paired with two Turbonetics TO4B turbochargers that together produced a pavement-warping 898 horsepower and 772 pound-feet of torque… in 1988. The Porsche 959, also on sale at the time, made less than half that amount of horsepower from its twin-turbo flat-six engine. While we live in a world today where a number of hypercars make more than 1,000 horsepower, there’s still huge respect for anything that can approach 900 horsepower, let alone a car that’s 37 years old.
Of course, the C4 Corvette of the day needed more than just power to reach such an impressive speed. Callaway focused on the car’s exterior, which at speeds of about 250 mph would be critical for keeping the car stable and avoiding… takeoff. The company created the Callaway Aerobody kit, which, to this day, is one of the best iterations of the C4’s styling.
The car’s new nose cone continues the hood’s lines down to the road with a soft vertical crease in the middle. The Corvette badge sits inches off the ground, while a quartet of air inlets rest between the car’s iconic pop-up headlights. New, lower rocker panels make the car look planted and incorporate large vents behind each wheel. And the rear end sports a small spoiler and lower valence with no less than four exhaust pipes lined up in the middle. Drag was lowered, stability increased, and those two turbos had all the air they needed thanks to this body kit.
The Sledgehammer’s suspension was upgraded for high-speed stability with relocated lower control arms and Koni shocks. The all-important wheels, meanwhile, were 17-inchers from Dymag and wore a set of Goodyear tires made specifically for the car’s top-speed attempt.
The car’s interior was fairly stock with A/C, power windows and locks, and a stereo. A leather-wrapped roll cage was installed along with a pair of modified OEM seats, and a plaque was mounted on the console signifying the Slegehammer was number 51 out of 400 standard Callaway TwinTurbo Corvettes that were made.
Where Is The Sledgehammer Now?
Only one Callaway Corvette Sledgehammer was ever built. As you can see, a lot went into making it, and producing it commercially wouldn’t have been feasible at the time. Nevertheless, Callaway capitalized on the car’s attention by working with Chevrolet to produce less powerful Callaway Corvettes, many of which retained the Sledgehammer’s coolest features.
The original car has changed hands between private owners a number of times during its life. The last time we were aware of that it changed hands was May 2021 when it was sold on Bring a Trailer. The car actually failed to sell during the original auction with a final bid of $500,000 that didn’t meet the reserve, but a deal was made after the fact with a reportedly respected collector.
Callaway the company has even stayed involved with the Sledgehammer all these years. The BaT listing says the company last performed service on it in 2018 when some hoses, couplings, and fittings were replaced. Unfortunately, Reeves Callaway, the company’s founder and driving force, passed away in July 2023, shortly after the Sledgehammer was last sold. Callaway Cars, though, continues on, making high-performance versions of vehicles from Chevy, GMC, and Cadillac, including the latest Corvette.
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