Tracy Hebert’s Boosted C5 Brings Drag Car Horsepower To The Highway
Tracy Hebert wanted to build a street car. In December of 2011, after seeking advice on the famed Yellow Bullet message board, Hebert began what he believed would be a six-month build project. He’d decided to build a twin turbocharged big block powerplant, expected to produce around 1,800 horsepower, while maintaining reasonable highway manners, then find a rolling chassis to drop it in when the engine was complete. Three and a half years and several significant changes later, Hebert is finally nearing the completion of the project.
As is often the case with garage builds, changes in technology, costs, and convention led to a series of alterations to the original plan. Tracy knew from the beginning that he wanted to build a boosted 509-inch big block Chevrolet, and that held true throughout the project. The basis for the engine, a cast iron Dart Big M block, holds a Callies Ultra-Billet 4-inch crank, while Oliver Maxi-Billet connecting rods and JE flat-top pistons complete the bottom end. On the busy end, Dart 345 heads hold T&D shaft rocker arms, Morel lifters, Manton pushrods, and Ferrea valves (stainless intake, inconel exhaust) and a custom Bullet Cams camshaft regulate the incoming and outgoing air.
The original plan was for a blow-through carburetor setup featuring a pair of Precision 7675 turbo units, but Hebert decided, after some friendly prodding on ‘the Bullet’, to step up the turbos and go with an EFI setup. He consulted John Bewley of Li’l John’s Motorsport Solutions (LJMS), one of the fastest-growing names in the realm of turbocharger science, who recommended the 80mm ForcedInductions.com turbos to meet Tracy’s request of power with manners.
Says Bewley, “With Tracy’s goals and the parts he had already purchased, the billet 80mm units were a perfect fit. They provide the potential for up to 2,600 horsepower worth of compressor flow, and have the right size turbine for the combination of track and street use this car was intended to see.”
That’s right, these changes brought an increase in Tracy’s anticipated performance, from an already-lofty 1,800 horses, to an asinine 2,600, and deep seven-second quarter mile times with reasonable manners on the streets of Hebert’s hometown of Lafayette Louisiana.
Cooling down the charged air is a Shearer 3,000 horse-capable intercooler.
Fueling such a high-output beast on the track and the street would be no simple feat. Alan Kennedy of Billet Atomizer recommended their 225 pound injectors, which are fed by a belt-driven Aeromotive fuel pump and mounted in a trick Thomsen Motorsports intake. Fuel containment comes in the form of a 10 gallon tank mounted behind the rear seats, and Tracy also opted for a Walbro electric pump to prime the system on cold starts.
Backing the engine is a BTE Powerglide featuring a TH400 output. Joining the trans to the powerplant is a PTC 9.5-inch torque converter, while a Precision chromoly driveshaft dumps the torque into a custom Scribner 9.5-inch rear housing loaded with a Strange Ultra center section and gun drilled 40-spline axles. Everything rides atop Afco double-adjustable shocks and Weld V-Series wheels. Hebert keeps two sets of rolling stock to meet the demands of street-and-strip use: 17×7-inch front runners and MT SR 18×29’s for street use and 15×4-inch skinnies with Hoosier QT Pro 16.5×31’s for track duty. Strange disk brakes bring things to a halt in short order once the fun is over.
As for the chassis itself, the C5 was purchased as a rolling chassis with the 6.0-certified cage and 4-link suspension already in place. Hebert left the raw-metal look in place, offering a stark contrast to the polished finish of the overall build, perhaps in homage to the dual-threat nature of the Corvette. Also lending to the car’s dual-personalities is the trick exhaust system Tracy designed and built. The turbos dump exhaust out just behind the front wheel openings when Hebert is ripping down the dragstrip, and for the ride home, a pair of five-inch cutouts redirect the spent gasses through the remaining factory-style exhaust routed out the back. A pair of Borla mufflers liven up the tame factory exhaust note, but the system does an admirable job of concealing the cars beastly nature when in “cruise” mode.
While the car is still short of 100% completion, Tracy has been able to take it for short drives through his neighborhood, which only served to stoke his fire to finish the remaining few bits and pieces so he can begin the process of tuning this dual-purpose monster.
While he certainly has nearly-insane performance planned, he did make some compromises in the build to ensure his comfort when cruising in the sweltering Louisiana summers.
Hebert made it a point from the beginning to have air conditioning in the car, and after his short test drives opted to add power steering as well. The car also features a copious treatment of Luxury Liner sound deadener, adding quite a bit of heft to the ‘Vette, but greatly reducing the interior drone and cabin noise from the monster rear tires. Hebert also says a max-effort build would have allowed him to go with a more aggressive cam and larger turbos, but he chose to compromise on both in favor of streetablity. Even with these compromises, this boosted big block C5 should have no problem putting nearly 2,000 horsepower to the ground and ripping of deep seven-second timeslips while keeping Tracy nice and comfy in the air-conditioned cockpit!