This Sledgehammer reached 254.76 mph at the Transportation Research Center (TRC) in Ohio and became the world’s fastest street-legal car for some time.

It was built up by Reeves Callaway in Connecticut as an example of what was possible with the new ZR1 and and turbocharging its LT5 engine.

The result was a 898 bhp coupe that still retained luxuries such as air conditioning and a radio.

Callaway achieved this power by using a NASCAR-spec block with Mahle pistons and forged connecting rods. The top end included a Brodix aluminum head which was fed by twin Turbonetics T04B turbochargers.

The suspension was addressed by Carroll Smith who lowered the entire car one inch and fitting 17-inch Dymag aluminum wheels with specially-made Goodyear tires.

On October 26, 1988 at 3:45PM John Lingenfelter drove the Sledgehammer to its record speed of 254.76 mph on the 7.5 mile oval track at the Transportation Research Center (TRC) in Ohio.

Story by Richard Michael Owen

1988 Callaway Sledgehammer Corvette Gallery

1988 Callaway Sledgehammer Corvette Gallery

In Detail

type	One Of
built at	Old Lyme, Connecticut, USA
production	1
price $	$ 400,000
engine	Twin Turbo V8
displacement	5733 cc / 349.8 in³
bore	101.6 mm / 4.0 in
stroke	88.4 mm / 3.48 in
compression	7.5:1
power	669.6 kw / 898 bhp @ 6250 rpm
specific output	156.64 bhp per litre
bhp/weight	565.14 bhp per tonne
torque	1046.7 nm / 772 ft lbs
driven wheels	Front Engine / RWD
front tires	275/40ZR-17
rear tires	275/40ZR-17
front brakes	Vented Discs w/Vacuum Assist & ABS
front wheels	F 43.2 x 24.1 cm / 17.0 x 9.5 in
rear wheels	R 43.2 x 24.1 cm / 17.0 x 9.5 in
steering	Rack & Pinion w/Power Assist
curb weight	1589 kg / -1.0 lbs
wheelbase	2443 mm / 96.2 in
front track	1514 mm / 59.6 in
rear track	1534 mm / 60.4 in
length	4483 mm / 176.5 in
width	1803 mm / 71.0 in
height	1186 mm / 46.7 in
transmission	6-Speed Manual
final drive	3.54:1
top speed	~409.9 kph / 254.7 mph
0 – 60 mph	~3.9 seconds
0 – 1/4 mile	~10.6 seconds

Auction Sales History

1988 Chevrolet Corvette Callaway Sledgehammer 1G1YY2180J5109700 – did not sell for $600,000 The Sledge Hammer was built to exceed all top speed records as the showcase for Callaway’s Turbo technology. On October 26, 1988 at 3:45PM John Lingenfelter drove the Sledgehammer to its record speed of 254.76 MPH. The Sledgehammer was driven from Callaway in Old Lyme, CT to the Transportation Research Center in Ohio for its record run. Hand built engine by Callaway using a 4-bolt main bowtie block rating up to 898 HP and 772 ft/lbs of torque. Auction Source: Kissimmee 2014, #WhereTheCarsAre by Mecum

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