Aug 31, 2020 update to the Chevrolet Corvette Z06 project car

Project Corvette Z06 | Magazine Series Part 1: Buying Guide and Finding Our Car

[Editor's Note: This article originally ran in the April 2018 issue of Grassroots Motorsports; for more updates, visit here.]

 

An old adage warns us not to trust what seems too good to be true. In most cases, that adage holds up. When the subject is the C5-chassis Corvette Z06, however, reality may be even better than it seems. Can this car actually be one of the easiest ways to go insanely fast–and for such a low dollar amount? 

Whatever the case, we couldn’t let everyone else have all the fun. C5 Z06s were constantly popping up on our computer screens during leisure-time searches, and article after article–some even in this magazine–insisted that the C5 Z06 was primed to be the next breakout modern classic, and sooner or later people would get wise to the deal and prices would begin to climb. We figured that we had to jump on the bandwagon before our own prophecies came to pass.

It’s been a while since we’ve had a C5 Corvette in the fleet, but this time we brought in the top model: the Z06.

Our Corvette Z06 is an evolution of the Fixed Roof Coupe, shown here. The FRC had stiffness and low weight; the Z06 added more power. Photograph courtesy General Motors.

Why You Want One

The Z06 is my favorite C5, and maybe one of my favorite Corvettes of the entire history of the car.” It’s a quote that could’ve come from any of thousands of car enthusiasts who’ve wheeled a C5 Z06 through snaking turns or down a long straight. 

In this case, however, that little truth nugget was uttered by none other than John Heinricy, the now-retired director of GM Performance and former co-chief engineer of the Corvette platform. Though his duties building America’s greatest sports car are behind him, he still spends dozens of weekends each year road racing and autocrossing GM products. And on many of those weekends, his product of choice is a C5 Z06.

The original plan was for the coupe version to perhaps be an entry-level Corvette model,” Heinricy says of the truncated-roof C5 that came to market as the Fixed Roof Coupe before evolving into the Z06 model. “What we eventually found was that it wouldn’t really be all that much less expensive to produce. And the fact that it was lighter and stiffer made it a more natural adaptation to a performance car than an entry-level car.”

We’re glad GM made the right call.

As Heinricy points out, the Z06 was an evolution of that 1999-2000 Fixed Roof Coupe model. The fifth-generation Vette had been introduced in 1997, and the FRC integrated some of the additional chassis bracing from the convertible platform while using a lighter roof structure that eschewed the large glass hatch found in the standard Corvette for a shorter greenhouse. The result was a Corvette that was lighter and stiffer than the standard model. The Fixed Roof Coupe came standard with the performance-tuned Z51 suspension, making it the best-handling C5 built to that date.

Of course, the sensible plan was to add more power.

The heart of the Z06 was the LS6. Producing 405 horsepower for the 2002-’04 model years, this V8 propels the Z06 to speeds more typically associated with supercars.

The first Z06 was introduced for the 2001 model year. It paired the FRC’s light and stiff structure with a 385-horsepower, 5.7-liter V8 dubbed the LS6. This was a 40-horsepower bump over the standard car. 

The Z06’s body got a few additional performance tweaks as well, like thinner glass, a titanium exhaust system, and some deleted sound deadening–all in the interest of weight savings. Performance was among the best of any factory Corvette in the marque’s history, and the car was a true world-class performer.

Not content to rest on the success of the ’01 model, Chevy cranked things up for 2002. A lighter valvetrain plus some intake system tweaks added another 20 horsepower to the tally. This 405-horsepower Z06 could rip the zero-to-60 sprint in about 4 seconds flat while lapping the track as fast as some of the world’s most expensive supercars.

The model received just minor improvements over the next two years, mostly in the area of reliability. New shock absorbers on the 2004 models were a substantial upgrade, but in broad terms the 2002 through ’04 cars are considered functionally identical.

Acquisition Proposition

We’ve probably convinced you by now that you need to add one of these to your garage. Fortunately, Chevy made plenty of Z06s to go around. But what should you expect to pay, and what do you need to look for when shopping for a C5 Z06?

Well, first we’d say to probably not bother with the 385-horsepower version sold for 2001. There’s not really enough of a cost savings to justify the missing power. If you plan to enter one in any organized competition, you’ll find yourself classed with the higher-powered versions and with potentially no legal way to close the performance gap.

That leaves the 2002-’04 models, which are basically identical. There were some running production changes on a few hard parts in the interest of durability over the years, but these differences may not really matter now. Chevrolet fit slightly different hubs to the later cars, for example, but today all of the replacement parts reflect the updated specs. Once you factor in normal service, the advantages of buying a later car start to evaporate. 

There is one running change that can make a difference, however: The switch to the lighter valvetrain parts for 2002 resulted in higher-than-normal rates of valve spring breakage. Most of those issues–nearly 70 percent–occurred in 2002 models. A smaller percentage occurred in 2003 cars, and only a statistically insignificant number was reported in 2004 cars. Chevrolet likely noticed the problem in 2002, made fixes in 2003, and perfected them the following year. 

Fortunately, replacing the valve springs on these pushrod engines is not a complicated or expensive process. A set of replacement springs costs less than $100, and any 2002 or ’03 Z06 should get the updated springs as a matter of basic maintenance. 

Aside from the valve spring issues, the only other consistent concern involves weak crank pulleys. The rubber bushing found in the crank pulley can deteriorate over time, allowing the pulley to wobble a bit. 

If left untreated, this can obviously create a bad situation. Fortunately, an OE pulley sells for less than $100 and should be treated as a wear item. We recommend installing the pulley with an ARP bolt. In any case, the OE bolt should never be reused, as its design will prevent proper torquing after its initial install.

Enginewise, these cars are beasts. A properly maintained LS6 is capable of running hard well into six figures on the odometer. We’ve heard stories of track cars covering more than 200,000 trouble-free miles. The bottom line is that maintenance, not mileage, should be your prime consideration when assessing a used car’s engine health.

The downside of a high-mileage Z06 usually comes in the form of interior wear. GM products of this era weren’t always known for having the plushest cabins with the most durable materials. A high-mileage Corvette will likely show wear on the driver’s seat in the form of ripped leather and worn foam, and the cabin will probably rattle and squeak as its plastic bits crack and deteriorate.

Our car was in great shape for its age and mileage, but showed some flaws in typical spots, like a cracked HUD bezel. The problem isn’t noticeable from inside the car, but those walking by can see it. Our driver seat also showed very typical bolster wear and foam degradation. A look through online sales sites showed us that our sales price was market-realistic.

The good news here is that this isn’t news to anyone, and the aftermarket has stepped up with repairs and solutions. Mid America Motorworks is one such source, selling complete seat rebuild kits–including replacement leather and foam–for less than $1000 for the pair. They offer replacements for most of the interior trim and plastic, too. For example, the Z06’s HUD bezel is highly prone to breakage and is also a pain to replace. Mid America has developed a replacement bezel that simply covers the broken one yet still looks factory. 

The takeaway message here is that fixes are available for weak interiors, but interior condition can still be an indicator of car health. If you find a 90,000-mile Z06 with a like-new interior, chances are good that the car was very well maintained overall.

When it comes to the chassis, some items do wear with age, but replacement costs are usually moderate. Control arm bushings will eventually work their way out of the arms, and the whole arm will need to be replaced as an assembly if the car runs under rules that require things to be kept stock. 

Aftermarket arms are less expensive than OE arms, but quality can be inconsistent and they tend to need more frequent replacement. Will that $400 OE control arm be four times better than the $100 aftermarket replacement? That’s the gamble. 

Overall, though, this is a GM product, which means economies of scale are in play for many of the parts. Since this is a popular GM product, even the Corvette-specific parts should be affordable. 

You Said That You’d Discuss Price

Yes, we’re getting to that. We’ve said before that these cars represent a great value for their performance, so let’s determine what you get for how much.

First we can look at “book” value, by which we mean what Kelley or NADA says the cars are worth. According to these guides, a clean 2004 Z06 with 50,000 miles should cost about $20,000. Add a little for a dealer sale, subtract a little for a private transaction, but 20 grand is the bogey. 

The book values were slightly lower than the real-life prices we saw while shopping. We wouldn’t say the book values are wrong, exactly; rather, these cars may be trending upward. 

Still, people constantly advised us that we could buy these cars all day long for $15,000. Uh, not really. Sure, $15,000 Corvette Z06s exist, but they’re rats, or they have a lot of stories attached. You get the idea.

We found the price range of the most favorable cars to be between about $19,000 and $23,000. You can buy a near-perfect, no-excuses, low-mileage Z06 for the higher figure, or you can buy a car with some warts for less–and by the time those issues are fixed, you’ll have spent up to the higher figure. 

We began shopping at the higher end of that range, since it’s easier to start a project with a car that hides no mysteries. And at $23,000, there really are Z06s available every day of the week all over the country, many of them coming through reputable dealers that offer inspections and pre-sale services. (Of course, there are just as many coming through super-sketchy dealers who would gladly finance you with a note that accrued interest every time you used a word with the letter E in it, so smart shopping is always in order.)

Ultimately, we ended up buying a car at the bottom of that scale because we liked the deal and the car itself. Our car is a 2004 Le Mans Commemorative Edition, which features a carbon-fiber hood that weighs 10.6 pounds less than the standard fiberglass piece. Now, we realize that 10.6 pounds is not going to be the difference between a national championship and last place, but if you have the opportunity to cherry-pick your C5 Z06 purchase, the Commemorative Edition is certainly the sweetest fruit. 

After we picked up our purchase, we took it right to Greenwood Motorsports in Evanston, Illinois, for a quick once-over. While there we also installed a set of BFGoodrich g-Force Rival S tires plus some ARP extended front studs. The latter were quick to install since the hubs remained on the car. 

Chevy only offered the Commemorative Edition for the 2004 model year and, as the name suggests, it celebrates the Corvette’s one-two finish at the classic French race. In addition to the carbon hood, these cars all wore the same paint scheme: Le Mans Blue with silver stripes. 

The blue books say that the Commemorative package commands a $1500 premium over a regular car in similar condition, which may be tough to swallow on the front end. However, we anticipate that premium growing as the cars begin their inevitable reappreciation cycle.

Asking price on our car was $18,500. It was owned by a Chicago-area autocrosser and track day participant, came with some extra wheels, and was stock with the exception of a Strano Performance Parts front anti-roll bar–a part we would have added anyway. The odometer showed 94,000 miles, and the car looked great in the photos. We called the price a little on the side of too good to be true.

Turns out there was some drama in its past. 

As soon as we got the seller on the phone, he told us the car’s backstory: “Just so you know, this car hit a tire wall at a track day.” Bonus points for the honest disclosure. 

Indeed, the seller’s brother had gotten up close and personal with the Turn 10 wall at Autobahn Country Club. Damage was limited to the driver-side fiberglass and some minor bumper cover rash. That valuable carbon hood was unharmed. The seller and his brother repaired the issues, even going above and beyond by replacing lots of suspension components out of sheer precaution. 

The work was well documented and seemed to be completed to a high standard. Still, there’s inherent risk in buying any once-damaged car, and our ultimate purchase–a little less than $18,000–reflected how much of a gamble we were willing to take. 

Now What?

The car was in Chicago, so we flew up from our Florida base to fetch it. Our first stop in our new Z06 was Greenwood Motorsports and Wagons in nearby Evanston, Illinois. Longtime championship driver Jason Saini manages the place, which specializes in cool machines–specifically sports cars and wagons. It’s a place to find unicorns. 

We put the Corvette on the lift and liked what we saw. The previous owner had done a great job on the crash repair. Fit and finish looked as good–maybe better–than new. And having fresh hubs and control arms on half the car is a nice bonus. 

Our new prize does show some wear on the driver’s seat, and a couple of minor interior parts had been replaced with nonstandard pieces. Overall, though, we’d describe the condition as very good. We’ll have to put a few bucks into it to get everything up to excellent condition, but considering what we saved on the buy-in, we’re okay with that.

We also had a set of BFGoodrich g-Force Rival S tires meet us at the shop. The crew mounted them so we could autocross with the Chicago Region SCCA the next day. 

We’d love to tell you how well the car handled, but we were greeted by 34-degree temperatures and a wet, barely thawed surface. Grip was nearly nonexistent during the event. Still, we got to enjoy our latest toy, so we’ll call the day a success. The drive home to Florida was comfortable and capable, with the Corvette averaging 24 mpg, right in line with the EPA’s figures. 

Our drive home also included a stop at Mid America Motorworks. In addition to nearly every possible Corvette restoration part, they also have an amazing museum that’s open seven days a week. 

In the next few installments of this series, we’ll focus on digging in and getting the car into shape. We’re initially going to run the car in SCCA Solo and NASA Time Trial competition in the stock-class ranks, so while our mod list will be short, we’ll still have work to do. Basically, we want to concentrate on maximizing the performance available from an already exceptional chassis. 

We’ll have plenty of time to achieve even more ludicrous speeds than the car is capable of now. Don’t worry, we’ll be busy with this one for a while. 

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