1990 Chevrolet Corvette ZR1 C4

1990 Chevrolet Corvette ZR1 C4

Conrad Webb’s 1990 Corvette went into hibernation in a barn for nine years and came out looking none the worse for its ordeal, as Paul Bussey discovers…

Conrad Webb’s family have always run American cars. Indeed, his father owned a 1964½ Mustang convertible that he purchased in California, drove it across America to New York, had it converted to right-hand drive and then shipped to the UK. “That was when my mother was pregnant with me, so I am a confirmed American car aficionado from birth, it’s all but in my blood,” he grins. “I remember we had a couple of Mach 1 Mustangs and then a Ford Torino Gran Sport. It was bright yellow and we used to thunder down to the South of France in this car, which only returned something like 12mpg. We’d pull into petrol stations at regular intervals and watch all the caravans that we’d overtaken at huge speed go by and then we went and did it all again. While it may have been the most brutally useless car ever, we had Ford station wagons over the years, as well as a Jeep Wagoneer. There were four kids in our family and so they were the more practical US vehicles we owned.”

1990 Chevrolet Corvette ZR1 C4

Conrad purchased his 1990 Corvette ZR1 brand new from Herrin-Gear Chevrolet of Jackson, Mississippi and it was just one of 3049 produced in the debut year of 1990. The ZR1 was unveiled a year earlier in March 1989 at the Geneva Motor Show. The price of the basic 1990 Corvette C4 was $31,979 and the full ZR1 performance package was a further $27,656. This included the 5.7-litre LT5 MPFI dohc 32-valve V8 engine rated at 375bhp, with 370ft-lb torque, which was designed by Lotus in the UK. Following development by Lotus, engines for production cars were built and supplied by Mercury Marine’s MerCruiser division, based in Stillwater, Oklahoma.

The transmission was an aluminium cased ZF ML9 six-speed manual with CAGS (computer aided gear selection). Other items in the ZR1 technical specification included a performance handling package, 17-inch alloy wheels, leather interior and all ZR1s were available as coupes only. The ZR1 was certainly a milestone car as far as Corvette production was concerned and was quite rightly referred to as ‘King of the Hill’ by Chevrolet chief engineer Don Runkle. Motor Trend magazine described the performance as: “Power flows from the ZR1 in a Niagara-like rush that makes the slick shifting six-speed seem ridiculously redundant.”

The main reason for purchasing the ZR1 was to drive between family homes in Switzerland and France along the French and Swiss autoroutes and then up through the Alps, and being left-hand drive the car suited the remit perfectly. “We also looked at the possibility of purchasing a Lister Jaguar XJS, which was incredibly fast, but cost well over £120,000, but for less than half the money the Corvette ZR1 offered truly superb performance,” he explains. “The ZR1 was ordered with the help of a family friend in Georgia. Upon delivery the car was airfreighted on August 7, 1990, courtesy of Lufthansa, from Atlanta to Zurich, Switzerland, at a cost of $7040, where it became Swiss-registered. The ZR1 provided a fast, spirited drive between Switzerland and France for the next four or five years, clocking up around 31,000 miles in the process.”

In about 1998, the Corvette was brought into the UK and immediately stored in a barn, where it was to remain for the next nine years. Paradoxically the car then became almost forgotten about to a certain degree. “When we imported the car from the US to Switzerland, at the time the import duty was relatively low, much lower than it would have been to the UK,” explains Conrad. “So there was a kind of double bonus of importing it to Switzerland, where we wanted to use it and incur lower import duty. Now we had a Corvette, no longer registered with the Swiss authorities and not registered in the UK either, as it had never been put on the road here.

“Eventually the Corvette came out of its long-term barn hibernation in 2007 and was UK registered, along with having to pay UK duties which amounted to £2978. After we had resurrected the car, the only real problems seemed to be with the six-speed gearbox.

Long-term storage wasn’t kind to one of the two fuel pumps, so we replaced both of them. Gear changing was a little notchy in fourth which wasn’t initially a big deal, but over time it became a nuisance, so we had Claremont Corvette (www.corvette.co.uk/email: parts@ corvette.co.uk/Tel. +44 (0)7836 388888) strip the ’box down and complete a full rebuild.” Other recommissioning work included fitting new brake pads, and a new set of tyres to the original specification were ordered from North Hants Tyres, which were shipped over from the US. These tyres are Nitto 275-40/ZR17 315-35/ ZR17, front and rear respectively. “I also tried to get the original alloy wheels refurbished, but due to their design, it was not possible to get the faces diamond-cut, so we decided simply to have the original protective lacquer removed and had them painted instead,” says Conrad.

Other than servicing consumables, the ZR1 is pretty much entirely original (a gearbox rebuild excepting) and it says much about the pigment in the red paint that the colour has lasted so long and not faded at all. However, when the car was in its long-term storage, it was kept in a plastic bubble which was vented to minimise any damp. Yes, there are a few stone chips on the lower valance, as you’d expect with 31,000 miles of travel on continental autoroutes, and there’s very minor wear to the interior.

“Around two years ago I did have the car professionally detailed, just to enhance its overall appearance,” points out Conrad. “The ZR1 is a fantastic car to drive, it’s a proper GT with plenty of storage space. You can tour Europe and pack everything, including your wife’s shoe collection! Most of my journeys involve long-distance trips, each one could entail up to 400-600 miles.

However, I’m also aware that because the car is so original and 57,000 miles is relatively low mileage for its year, it’s not my intention to clock up a vast mileage, but not using it too often is also not an option. I’d rather replace parts that have worn out through natural wear and tear, rather than having them seized up from lack of use. About three years ago I attended a wedding in Sicily with my partner and we drove the Corvette there, through the Alps and down through Italy, where it performed faultlessly, and maybe in the future we’ll embark upon another European trip.

“Like many cars, they are specifically factory tuned to pass all manner of various emission tests and the ZR1 was no different,” continues Conrad. “After a while, the car began to develop a certain hesitancy upon acceleration and so I purchased an aftermarket add-on chip from Marc Haibeck of ZR1specialist.com that’s simply stuck on top of the ECU and removes the original emission control mapping for the injection system. Fitting it took only 10 minutes and now what we have is a completely smooth power delivery in all gears and rev ranges, and I like to think it is now much more akin to what the Lotus engineers originally developed.

“I have to say, overall reliability of the ZR1 is impressive. A recent minor issue was with the windscreen-wiper washer system, when no water appeared, which was actually traced to the windscreen fluid having gunked up and blocked the filter. The original motor was still working okay, but it’s things like that you expect to replace after 29 years.”

Conrad intends to keep his ZR1 for the foreseeable future and one of the next jobs looming will be to replace or maybe refurbish the original telescopic dampers. He has replaced some rubber seals which had started to crack, and another job scheduled for this winter is to replace the exhaust system. A good many years ago, he sourced a genuine GM item which was taken off another 1990 ZR1 that had only covered a few thousand miles from new. This car is certainly used like a true GT, stretching its legs over large distances fairly regularly. While the design and styling may be slightly dated now, compared with the modern state-of-the-art Corvette C7, there’s no denying that the ZR1 and all it stood for back in 1990 still cuts an extremely impressive dash today.

ZR1 spent about nine years in hibernation. 5.7-litre LT5 MPFI dohc 32- valve V8 was designed by Lotus. ZR1 is a true Nineties classic American. Power lumbar support.

Aluminium ZF ML9 six-speed manual offers sporty shifting. Air bubble storage has resulted in an immaculate car. Body-hugging leather seats. A total of 3049 ZR1s were built Body-hugging leather seats. for the 1990 model year.

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