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Pushrod Domination - 2004 Chevrolet Corvette Z06

Revenge Of The ber-Geek

By Jay Chen, Photography by Brian Booth

USCC Contender 04Love it or hate it, the C5 Corvette Z06 comes with a respectable list of features. It's lighter than many popular imports (such as the Evo, STi and 350Z), and benefits from a lower center of gravity, wider track, longer wheelbase, and better static weight distribution. You can fit a ridiculous amount of rubber with no body modifications. And the race-ready, forged aluminum, double A-arm suspension is symmetrical, with identical front and rear components, allowing for fully adjustable alignment settings from the factory as well as corner weights.

Out of the box, early C5 Z06s made 385bhp, but the 2004 model year stepped that up to 405. The American icon is also ridiculously responsive and minor bolt-ons will churn out a daily driven, track-ready Evo, STi and GT-R killer-as long as you can live with the horrific GM interior.

When it comes to crazy, daily driven 'Vettes, tuned for domination on both street and track, few are as good as this 2004 Z06. It's an example of a project car thought out and built to a level we should all strive for. The car was purchased used two years ago, with only 3000 miles on the clock, by Steve Ruiz, head geek at StopTech. He had only one purpose in mind: to build the ultimate daily driven project car using readily available bolt-on parts. Oh, and it had to beat a Ferrari Enzo in pure performance.

Even with such lofty goals, the modification list remained short and simple. The 5.7-liter, all-aluminum, LS6 small-block V8 remains untouched internally. To push power output into the 500 to 550 ballpark (at the wheels), Ruiz added a high-efficiency Magnuson air-to-liquid intercooled supercharger system. The blower pushes a peak boost of 7psi into the stock 10.5:1 compression engine and then out through LG Pro long-tube exhaust headers with high-flow cats and a crossover pipe.

The suspension consists of off-the-shelf pieces: Hotchkis anti-roll bars, stiffer composite transverse leaf springs with upgraded adjustable endlinks and custom re-valved Bilstein shocks. Simple enough. To make the car withstand this abusive amount of power and torque, Ruiz added a twin-plate Exedy clutch and flywheel, along with some robust ARP flywheel bolts. Being head geek at Stoptech also allowed Ruiz to install a set of carbon composite race brakes, originally developed for Speed World Challenge GT Corvettes.

One weakness discovered with the Magnuson supercharger system was its tendency to throw drive belts before eating them, which occurred several times during initial testing. Like any good engineer, instead of just sucking it up and buying another drive belt, Ruiz redesigned the belt tensioning system to incorporate a second OE tensioner. The car has been on the same belt since. A custom oil catch tank was fabricated to drain excess oil from the valve covers under hard cornering, instead of allowing it to be drawn into the intake through the breather.

Other details are invisible to the unknowing. To make sure the power was useable, Ruiz also customized a Racelogic aftermarket traction control system to rein in wheel spin without interrupting proper ABS function. The C5's OE wheel bearing assemblies (a known weak point) were replaced with GM Motorsport wheel bearings, as well as ARP wheel studs. In order to fit the massive 345/25/18 rear tires, the rear fender and liners were reworked with composites for a seamless OE fit and finish, instead of the usual fender rolling and gutted wells.

By Jay Chen
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