Low Down

Does the fourth-generation ZR-1 deserve more respect than it currently garners? We examine one ownership experience to help find out.

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October 28, 2011

As the owner of a 1991 ZR-1, Jeff Moore is entitled to an opinion about the first Corvette “supercar.” He’s owned the vehicle for five years and driven it over 10,000 miles. “ZR-1s get a bad rap for being unreliable and there being a lack of replacement parts,” says Moore. “It’s just not true.” He’s had no significant problems with his ZR-1, and he’s found the few parts he’s needed without difficulty. Another myth that Moore wants to dispel is that the car’s 32-valve 4-cam engine is impossible to work on; he’s repaired it himself. What really bugs Moore the most, though, is the fact that what he sees as misconceptions have dragged down the value of his Corvette. He paid $30,000 for it in 2005, but despite the car’s pristine condition, high degree of originality and low mileage (17,000 miles), “I’d be lucky to get $25,000 for it,” says Moore. It’s not that he’s in a rush to sell his car—it’s more that he feels the ZR-1 isn’t being appreciated for the unique, low-volume, high-performance vehicle that it is.

The ZR-1 is Moore’s dream car. He remembers reading about the rumored “King of the Hill” Corvette back in the late ’80s, and got swept up in the feverish anticipation that accompanied the media coverage. The first murmurs of the existence of a high-output C4 came in 1986, but it wasn’t until the following year that anything close to the real facts about the car started to come into focus. The September 1987 issue of Automobile correctly discussed the car’s Lotus-designed 32-valve overhead-cam engine. The article included a spy shot of a test mule with a bulging hood that certainly whetted the appetites of enthusiasts like Moore.

In June 1988, journalists at Riverside Raceway witnessed a ZR-1 test car blow past them at high speed, further confirming the existence of the model. A few months later, they were allowed to get up close and personal with the machine and get a full run down on the LT5 engine. They learned that although it shared the small-block V8’s time-honored 4.40-inch bore-center spacing, it was an entirely new engine with the ability to rev past 7,000 rpm and an output near 400 horsepower. The assembled media reported that the car would be released the following year as an ’89 model. Though that had been the plan, the ZR-1 did not debut until the 1990 model year, with its Mercury Marine-built LT5 officially rated at 375 horsepower and 370 lbs-ft of torque.

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All this media build up led to a lot of pent-up demand, which in turn resulted in some big dealer markups. In some isolated cases, the ZR-1’s $58,995 base price ballooned into the six figures. Moore, as well as many other young American-car enthusiasts, couldn’t afford such a royal price tag. He stuck with the ’84 he owned at the time, but never stopped thinking about the ZR-1.

In addition to its special motor, Moore liked the car’s unique bodywork—the subtle way it begins to taper out, beginning at the doors, to accommodate a 3-inch-wider rear-bumper. This ZR-1-specific fiberglass was needed to cover its massive rear wheels and tires. While the front 9.5 × 17-inch wheels (shod with 275/40ZR17 tires) were shared with the standard Corvette, the rear 11 × 17-inch wheels (with 315/35ZR17s) could only be had on the ZR-1.

In 2006, Moore decided the time had come to sell his ’84 and step up to a ZR-1. And not just any example: He wanted to find a pristine, all-original one with a well-documented history and minimal mileage. With the help of members of the ZR-1 Net Registry, he found just what he was looking for—in only three days. With a mere 6,000 miles on its odometer, this ’91 was still wearing its original tires. Moore had sought out a white ZR-1, and while he wasn’t so keen on the red interior, he figured this concession was a small price to pay given the car’s condition.

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But while the Corvette was in great shape, it wasn’t quite up to Moore’s exacting standards. “I wanted the car to be perfect,” he says. The first order of business was the rolling stock. The wheels’ clear coat was peeling off and the 15-year-old tires were rock hard. Instead of hassling with having the wheels refinished, he elected to buy a set of new, original-equipment ’96 Grand Sport wheels, since they were exactly the same size and readily available. He planned to fit proper ZR-1 wheels once he found them—a project that ended up taking five years. (Moore only bolts them on for show.) As for tires, he went with a set of BF Goodrich G-Force T/As.

Moore next set about fixing the car’s various small scuffs and scrapes. In the case of the blemished ash-tray door, for example, he chose to replace it with a new part. The long strip of side trim that runs along the front quarter panels and doors was removed and repainted. Moore did this himself, thanks to a friend who let him use his professional paint bay. While he was at it, he also resprayed the headlight buckets.

With these chores completed, Moore had corrected the ZR-1’s cosmetic blemishes, but the car’s appearance was still lacking in his judgement. Having come of age in Fremont, California (where he resides today) during the cruising scene of the ’70s, Moore has an affinity for lowered cars. From the first Chevelles he owned to his ’84 Corvette, all of his cars have sat closer to the ground than stock. So out came the ZR-1’s standard front spring and in went a Vette Brakes item, which allowed him to dump the front end by two inches. A pair of 12-inch-long spindle bolts let him drop the rear by over three inches. The result is one seriously slammed Corvette.

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Not surprisingly, having such a low ride height does have its drawbacks. At first, it caused the rubber front spoiler lip to scrape just about everywhere. This led Moore to cut it down by five-eighths of an inch, which was a big help. Of greater concern are the various parts of the ZR-1’s undercarriage, including its exhaust pipes; care must be taken on driveways and on just about any abrupt elevation change. “This car does not do speed bumps,” says Moore. As a result, his drives involve some advanced planning, as well as a high degree of caution.

But drive he does. The Corvette’s previous owner—its third—didn’t want to drive it for fear of adding to its low mileage, which is why he ended up selling it. Moore has no such fear. While 11,000 miles over the course of five years might not seem like a lot to most people, to owners of collector Corvettes it’s a considerable amount. Though Moore avoids driving it in the rain, he’s not afraid to get his ZR-1 dirty.

With added mileage and the passing of time come increased maintenance, as well as the possibility of needing replacement parts. A few thousand miles into Moore’s ownership, it became evident that the fuel injectors required replacement—a not-uncommon problem. One theory is that the higher alcohol content in modern fuels eats away at the injector coils, causing their early demise. Whatever the cause, the fix is clear: replace the fuel injectors. It is at this juncture where we can see how the Corvette ZR-1’s bad reputation was born.

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First of all, many mechanics don’t want to touch an LT5 engine, throwing up their hands in the face of its complexity and unique parts. To the uninitiated owner, this could be a thoroughly troubling situation. Thanks to the supportive ZR-1 Net community, however, Moore wasn’t one of those. He learned that replacing the fuel injectors was so straightforward that he could do it himself.

Armed with a service manual and the phone numbers of fellow ZR-1 owners, he started by pulling the plenum. “It was a little scary,” admits Moore, but he had no difficulty in carrying out the rest of the job, which includes removing the fuel rails. Nor did he have trouble finding parts. The fuel injectors can be purchased at the parts counter of any Chevy dealer, as they are exactly the same as L98 injectors; the only difference is that you need to buy 16 of them, not eight. Acquiring the proper gaskets, which have to be replaced each time the plenum is pulled, is a different matter. These can’t be found at a dealership, which can cause some to panic. However, a quick online search reveals they are in plentiful supply. Original-equipment gaskets do command a premium on eBay, but remanufactured ones from Gerry’s Gaskets are reasonably priced. The same is true of water-pump gaskets.

However, there are a few LT5-specific replacement parts that are prohibitively expensive. A thermostat housing will set you back a cool $500. (Moore is considering buying one now, before the price gets higher.) A transmission goes for roughly $1,500. Need to replace an entire engine? We found a 405-horsepower version (output went up in ’93) with a $12,500 price tag. Sadly, the high price of such parts combined with the car’s relatively low resale value has led some owners to part-out their ZR-1s instead of selling them whole. This is a sad state of affairs because the ZR-1 is such a great car to drive.

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Moore’s ZR-1 is impressively free of squeaks and rattles, especially since the lowered suspension makes the car’s ride quality fairly stiff. The car’s handling is satisfyingly sharp; this Corvette turns into bends without hesitation. However, the fear of scraping the ZR-1’s immaculate underbody does detract from the driving experience.

The LT-5 engine is a real gem. It revs so smoothly and with such eagerness that it’s easy to forget to upshift. No other Corvette engine spins this freely. Yet the LT5 still pulls hard from low revs, a trait it shares with its overhead-valve brethren. Sure, it’s doesn’t have big-block torque off the line, but there’s no waiting for this V8 to come on-cam, either. In this regard, the Z06’s LS7 is peakier; it delivers a much bigger wallop, but you have to wait until around 4,000 rpm for it to hit. The LT5 compensates for its relative lack of torque with its incredibly linear response. Plus, it has enough oomph to make the ZR-1 feel fast, even by modern standards.

“Someday, people are going to wake up and see this car for what it is,” says Moore. That day may be getting closer. Our most-recent C4 Buyer’s Guide (July 2011) showed an upturn in ZR-1 values. Prices for the ’90 ZR-1 were up a solid 16 percent, and the other model years posted either mild appreciation or no change in value. After years of steady depreciation, this change represents quite a turnaround, but whether it marks an impending boom or merely a market correction is anybody’s guess. What is clear, however, is that the ZR-1 is a special Corvette. Its production numbers are low and its performance is high, and the free-revving LT5 delivers a unique driving experience. It deserves respect.

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