Chevrolet Corvette Callaway Twin Turbo Convertible

In the mid-1980s, while the C4 Corvette remained GM’s top performance model, its relatively low production volume failed to convince company brass that it deserved the investment needed for consistent development. The 230-hp 350-cubic inch TPI engines were just not cutting it, and the much-anticipated four-cam, 32-valve ZR1 remained in developmental limbo.

Callaway Cars in Old Lyme, Connecticut had been building high-performance turbocharger packages for a number of manufacturers. GM purchased one of Callaway’s twin-turbo Alfa Romeos and discovered that it ran rings around the Corvette. A meeting quickly ensued, and just a few months later, Chevrolet announced a new Corvette option for 1987. Called Regular Production Option B2K, it specified a 350-cubic inch Corvette V8, with breathing enhanced by a pair of small turbochargers. Notably, it marked the first externally supplied Corvette high-performance package that was available through participating Chevrolet dealers and covered by a full GM warranty!

Power output began in 1987 with 345 hp, growing by 1989 to 382 horsepower and 560 ft-lbs of torque. To handle this massive output, a Callaway-modified GM Turbo 400 automatic replaced the Corvette’s standard 700R4 automatic transmission. The carefully engineered swap included the addition of a Laycock deNormanville-type overdrive unit, as well as integration with the Corvette’s Delco Powertrain Control Module. Only ten Callaway Corvettes were equipped with the automatic option in 1989, which also marked the first year of availability of the ZF six-speed manual transmission.

The finished product was impressive to say the least, with 0-60 times in the mid four-second range and quarter-mile elapsed times in the 12-second range! Top-speed potential approached 180 mph. While these extremely limited-production Corvettes offered supercar-type performance, they were also surprisingly easy to maintain, with everyday drivability.

This car was auctioned off by RM Auctions in June of 2010 at the Town and Country Resort & Convention Center, San Diego, California.

382 hp, 350 cu. in. V8 engine, twin turbochargers and electronic fuel injection, Turbo-Hydramatic 400 three-speed automatic transmission with electronic overdrive, four-wheel independent suspension with front and rear transverse leaf springs and stabilizer bars, and four-wheel hydraulic disc brakes. Wheelbase 96.2".

Source: RM Auctions
Photo Credit: Copyright Darin Schnabel

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