Overdosing on Corvettes: The Callaway Sledgehammer

Callaway Sledgehammer


Over the past few weeks, from the long-awaited reveal of the C7 Corvette to the first 2014 production model’s sale at Barrett-Jackson, there has been a great deal focus on Chevrolet’s legendary affordable sports car. This got me to thinking about significant examples in the model’s 60 year history. The rarest? Easily the 1983 C4. Chevrolet skipped the 1983 Corvette model year for consumers, but as the company moved from the C3 generation to the C4, they still had to create test mules to develop the new model; 43 prototypes were built, and 42 were destroyed. The only survivor currently resides at the National Corvette Museum, and won’t see the light of day unless General Motors goes belly up and has to sell the collection, or a zombie apocalypse wipes out most of the population of the U.S., leaving survivors free to take any car they damn well please, à la Zombieland. Now, while I normally wouldn’t wish an undead horde upon my worst enemy…

But I digress. The ’83 is off limits (and is really just a normal C4, complete with an anemic V8 and a 4-speed auto), which brings us to #2 on the rarity list: the Callaway Sledgehammer. It too, is 1 of 1, but it was sold at Barrett-Jackson back in 2004, so that makes it fair game. The Sledgehammer was a one-off production model intended to show off not only Callaway Cars, Inc.’s dedication to high performance machines, but also to prove that a car could be the fastest in the world and also be drivable in normal street situations.

Like all of Callaway’s creations at the time, the Sledgehammer started life as a normal C4 Corvette, and then shot to the top of the class when a pair of turbos was added under hood. Normally, the Callaway Twin-Turbo lit the rear tires with a blistering 345-400hp at a time when the standard C4 made 245. The Sledgehammer was not a normal Callaway TT, however. That car somehow contained more than 900hp and could actually put that on the ground without the track melting.

The car that started out as the “Top Gun” project to create a record-setting street legal supercar morphed into the one-off Sledgehammer. Reeves Callaway commissioned NHRA driver John Lingenfelter and his engineering team to create a motor not only able to produce a tremendous amount of power but also balanced enough to be usable in everyday driving conditions. 250mph was the magic number for Callaway, and with that in mind, Lingenfelter got started. A hand-built 355ci V8 with twin Turbonetics turbochargers would power the Sledgehammer, and was rated at more than 900hp and 772 lb-ft of torque.

Paul Deutschman of Deutschman Design was charged with creating the aero and bodywork. Deutschman not only had to figure out how to feed air to the turbochargers, but also how to create enough downforce to keep the Sledgehammer stuck to the ground during high speed runs. A full body kit with ground effects and air intake ports was the solution, and a roll cage was wisely installed, just in case. The final body design was dubbed the Callaway Aerobody and was subsequently made available for purchase to Callaway TT owners.

By October 1989, the Sledgehammer was complete. On October 19, Lingenfelter himself took the reigns and blasted the Sledgehammer along the 7.5 mile oval track at the Transportation Research Center in East Liberty, Ohio; it hit a top speed of 254.76mph. As a testament to the car’s practicality, it was then driven all the way back to Callaway’s shop in Old Lyme, Connecticut.

Today, the Sledgehammer is well-known in enthusiast circles as one of the fastest Corvettes ever created, and arguably the best C4 in existence. A private collector bought the car at the 2004 Barrett-Jackson auction and remains unknown, although the ‘Hammer is known to escape its garage and turn up at auto shows from time to time. If released for auction today, it would easily exceed the paltry $221,400 it was purchased for nearly 10 years ago.

Thanks to,,, and for the information used to create this article.


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About Cameron Rogers

Cameron Rogers is the founder and lead writer at Downshift Autos, the only automotive blog on the Internet*. Born in the back of an AMC Gremlin, Cameron vowed to never let this extraordinarily embarrassing detail define him, so help him God. He drives a GTI but absolutely will not shut up about it if somebody asks. He will not hesitate to let people know that no, they shouldn't get a Porsche 911 when a Morgan 3 Wheeler is so obviously the superior choice. He is obsessed with the seats of a Carrera GT and the steering wheel of a Fisker Karma. He once sat in the driver's seat of a Tesla Model S, his greatest accomplishment to date. He is just now realizing that writing an autobiography, however miniscule, in the third person is odd and unnerving. *As of this writing, Cameron has been informed that there are, in fact, many websites and blogs centered around cars and car culture. He regrets his grievous error.

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