Long ago, in the era of Nintendo, Reaganomics and Devo, there was the C4 Corvette. Considered to be the most high-tech Corvette ever produced up to that point, the 4th-generation car did little to appeal to the hardcore enthusiast during that time period or in the succeeding years since.
Overshadowed by both earlier and later iterations of Chevrolet’s plastic fantastic, the C4 has since lived a life of obscurity and abandonment from all but the most passionate Corvette aficionado.
Now while you can certainly make a case for the LT4-powered Grand Sport of ’96 and the ’90-95 LT5 ZR-1, there is one car that is often overlooked and forgotten; the Callaway Twin-Turbo Sledgehammer! Powered by a NASCAR-spec small block and equipped with a forged bottom-end with Mahle pistons and Brodix heads, the stout long block made for one solid foundation of the intended power that lie ahead.
Not content on natural-aspiration for power, Callaway attached a pair of Turbonetics turbochargers with enough boost to push the power output of the TPI-based Corvette to the tune of 898 hp and 772 lb-ft. of torque! That’s impressive by even today’s standards. Callaway also sought the help of Paul Deutschman to tweak the C4’s shape to make it as slippery as possible including the body’s aerodynamics; maximizing airflow, reducing lift, and making the intercooling system much more efficient.
Suspension tuning was completed on behalf of Carroll Smith, who was charged with improving the suspension so much as so it could handle a car with nearly 1,000 horsepower and provide enough stability for 250-plus mph. Seriously.
They were so adamant that it could be done, that they took the Corvette to a track in Ohio once it was completed and convinced John Lingenfelter to pilot the car around the oval. After a few failed attempts (all of which were over 200 mph), it was on their fourth try that Lingenfelter and the engineering crew accomplished their goals, and then some, setting a 254.75 mph run around the 7.5-mile oval. The rest, as they say, is history.
Rick Seitz is the owner and founder of GMEFI Magazine, and has a true love and passion for all vehicles. When he isn’t tuning, testing, or competing with the brand’s current crop of project vehicles, he’s busy tinkering and planning the next modifications for his own cars.
