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2003 Chevrolet Corvette Z06 - Adhering to the Rules

Having walked out on a Viper, an NHRA scion discovers that Z06 Vettes are what drag-racing fun is all about

Christopher R. Phillip Jun 26, 2007
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"My dad told me there are just a few cardinal rules of racing: power to weight, gears and tires, and cubic inches. That's why I went with a Corvette Z06."
-Andrew Spada IV (talking to VETTE, March, 2007)

It's a good thing Dodge has silly rules, or Andrew Spada IV might be driving a Dodge Viper today. As the son of a professional racer, Andrew's predilection for fast cars was virtually preordained. That he would eventually settle on a Corvette was far from certain, however.

First, a little background. Andrew Spada III is a former NHRA Division II racer. He competed from 1965 to 1985 with AA/Gas cars, injected 472 Hemis, and Top Fuel dragsters. He ran the 1978 Winternationals and the 1981 Snowbird Nationals, beating Shirley Muldowney in the latter event's time trials.

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The younger Andrew grew up in Wesley Chapel, Florida, and learned to love drag racing at an early age. He began racing professionally in 2002 and races a Super Comp class dragster at Gainesville Raceway. He is currently studying with two-time world champion Top Fuel and Funny Car racer Frank Hawley, in the hopes of moving up to alcohol-class racing.

In 2003, Andrew enlisted his father to help him find a street/track car. First, they looked at an '02 Pontiac Trans Am outfitted with a stock LS1 engine. Although Andrew liked the look of the TA, the LS1 was crammed so far back in the subframe that the modifications he had in mind would have taken a superhuman effort to perform. He passed.

Next, the two set their sights on an '03 Dodge Viper SRT-10. But Dodge had a decree: Only current Viper owners could buy the latest version. Here's how the conversation went:

Andrew: "So if I handed you $80,000 cash, you wouldn't sell me this Viper?"Salesman: "If you handed me $180,000 cash, I couldn't sell it to you."

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So the pair made a trip to a Chevrolet dealer, where the younger Andrew fell in love with an '03 Z06. The two men studied the Z closely.

The elder Spada had thirty years of drag racing history behind him. He told his son, "If we're going to buy a Vette to race, it's got to adhere to my cardinal rules." The men looked at the motor, they looked at its output and its weight, and they looked at its capabilities.

According to Andrew, it didn't take long for the Z06's merits to become obvious. "We did a little more research, and after looking at the specs, we knew that the Corvette was the best platform. The first thing we looked at was how the engine was placed in the car. Then, we looked at the weight. These two areas checked out fine. We looked really hard at the Z06. We felt it offered the best bang for the buck, especially if you're going to do modifications."

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As an up-and-coming NHRA racer, Andrew was hot to boost the LS6's output above its factory rating of 405 hp. He added a wilder cam, a FAST 90mm intake, a set of Kooks 1 7/8-inch long-tube headers flowing through a 3-inch midsection and B&B Tri-Flo mufflers. In dyno tests, the Vette hit 438 hp and 401 lb-ft at the rear wheels. It was a good start.

Andrew then pulled the stock "243" heads and sent them to Pete Incaudo of VMAX Motorsports in Land O' Lakes, Florida. Pete tells VETTE the heads were CNC ported and polished, then outfitted with REV valves and dual springs good to 0.650-inch lift. Angle milling to 57 cc created an 11.5:1 compression ratio. The intake ports flow 310 cfm open (292 cfm with the intake installed), while the exhaust ports flow 225 cfm with no pipes installed.

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To support that airflow, a Comp Cams custom grind with 244/248-degree duration, 0.612/0.620-inch lift, and a 114-degree lobe-separation angle was installed. Post-install dyno tests produced 478 rear-wheel hp. Life was good.

Unfortunately, those good vibes wouldn't last. During a series of follow-up dyno pulls, the LS6 sheared a piston, ruptured a water jacket, and basically converted itself into a hyper-expensive, 450-pound aluminum paperweight. Although devastated, Andrew was not to be sidelined.

He called Scoggin-Dickey Parts Center in Lubbock, Texas, where sales specialist Marty Morris suggested one of the company's 402 short-blocks to replace the crippled LS6. Andrew agreed and waited patiently for his Vette's new bottom end to arrive.

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We spoke to SDPC's Tim Cooks about the company's custom-order LS short-blocks. "Our 402, 416, and 427 packages are really good performers and [are] heavy duty," Tim told us. "Spada's 402 is based on a GM LS2 aluminum block with a 4.005 bore and a 4.00 stroke. The rotating assembly...[uses] a Callies forged crank and Diamond pistons manufactured with a 2618 HD forging and topped at 14 cc. Callies Compstar H-beam connecting rods [are] held in place with ARP bolts. We balanced the entire rotating assembly before we shipped it. Because these packages are custom-ordered, we can supply, install, and balance whatever components the customer prefers. Eagle, Manley, and Lunati are some examples."

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Once the short-block arrived in Florida, Spada arranged for Michael Huser of Tampa-based Chevy MD to perform the installation. According to Michael, dropping the newer-generation block into the C5 posed some specific challenges. "The 402 had arrived with knock-sensor-relocation wiring. I relocated the sensors to the two empty holes on the passenger side of the block, near the motor-mount holes. I also had to trim away at the motor-mount bracket on the passenger side, which allowed the LS2 block to sit flat in the Vette's subframe. The cam sensor on the LS2-based 402 was different as well. We had to use a timing-gear set for the LS2 and run the Vette's ECU cam sensor off the LS2 timing cover."

The induction system comprises a ported version of the same FAST 90mm intake and a Comtech 90mm throttle body. Racetronix 42-lb fuel injectors squirt fuel delivered by the stock GM fuel pump, while MSD coil packs and wires team with NGK iridium plugs to light the mixture.

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A GM T56 transmission with hardened output shafts handles the shifts. The clutch is a C6 Z06 assembly, paired with a factory LS6 flywheel and slave cylinder. Somewhat surprisingly, the differential remains stock and is still loaded with the original 3.42 gears.

The suspension has been upgraded at all four corners with QA1 adjustable shocks. Lightweight CCW SP550 wheels wrapped in BFG rubber shear a few pounds and contribute to the Vette's race-ready appearance.

If there's one thing a son learns from his drag-racing father, it's that the lighter the vehicle is, the quicker the e.t. will be. So Andrew got to work. He pulled the Corvette's entire A/C and heating assemblies. He removed all of the climate-control ductwork and replaced the fiberglass stock hood with a carbon-fiber alternative. Since our photo shoot, he's gutted the power-window regulators, motors, wires, and switches and replaced the glass windshield and door windows with riveted-in-place and slider-controlled Lexan polycarbonate sheets.

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Even that wasn't enough. Andrew purchased a carbon-fiber racing battery from Braille Auto of Sarasota, removing another 27 pounds of weight from the Vette. He replaced the factory starter with an AeroSpace lightweight unit and saved another 11 pounds. He pulled the Z06's leather-clad thrones and bolted in AeroSpace racing seats good for 40 pounds of weight reduction. While he was at AeroSpace, he also picked out lightweight brake components, saving the Vette 24 pounds in the front and 31 pounds in the rear. Even the factory steering wheel was tossed aside in favor of a Sparco racing unit.

All in all, the Vette was lightened 326 pounds, giving it a race weight of only 2,990 pounds-with Spada at the wheel. Factor in a chassis-dyno-verified output of 552 hp and 501 lb-ft, and Andrew says the car is good for 10.30 e.t.'s at 133 mph.

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Future plans for the Vette include CNC-ported L92 heads and an APS twin-turbo kit. Spada's idea is to run 15 psi of boost and pull 960 hp/750 lb-ft with his next combo. Cylinder-head guru Pete Incaudo says Spada might even follow his advice and push the boost to 22 psi on a reduced 8:1 compression ratio.

But that's for a future article. For now, engine installer Michael Huser sums up Spada's 402-cube Z06 thus: "It's a solid, strong daily driver. I think you could drive it to Disneyland and take your girlfriend with you too."

Disneyland? Do they have a sanctioned quarter-mile track? We'll have to get back in touch with Andrew Spada and let you know.



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