September 14, 2004

By Robin Jenkins

Marathon running is a brutal sport. Pheidippides and Philippides are the names mistakenly given the historically unidentified Greek messenger whose 26-mile-jog the race commemorates. He died of exhaustion 2500 years ago upon completing his mission, yet his name was lost to posterity. Today we more often celebrate Olympic sprinters, forgetting that endurance is a surer mark of health and determination. Perhaps because it takes less than ten seconds to watch a sprint, those who run for hours don¹t as readily capture our attention.

The same can be said for automobile racing -- 24-hour races are rare; 5000-mile races even more so. But, lest another true hero be forgotten in annual disputes over which new car quarter-miles the quickest, let¹s be clear in this Olympic year about the undisputed marathon champion of production cars -- the gutsiest distance-racer ever mass-produced. It was All-American in spirit, but reflected a bit of Olympic brotherhood in borrowing from both Great Britain (engine) and Germany (transmission). Its singular mission was to best a strong Japanese competitor in the ³all-around² event, but it stunned the automotive world by running a marathon that wouldn¹t be beaten for an entire decade.

Beginning in 1990 and ending with the 1995 model year, General Motors sold 6,939 Corvettes designated ³ZR-1². Not to be confused with its more primitive namesake offered 20 years earlier, this new ZR-1 was both luxuriously appointed and the fastest car built in America at the time -- not only in acceleration, but on the highway in particular. There were two features exclusive to every new ZR-1: each car came with a purpose-built, 32-valve, 4-cam, aluminum, LT-5 engine; and each was three inches wider in the rear than its sister Corvettes, in order to accommodate wider rear wheels and tires. Neither feature was obvious to the casual observer, but one of them made all the difference.

³The Heart of the Beast², as the ZR-1¹s LT-5 engine came to be called, was a huge departure from GM¹s traditional manufacturing style. It was designed in collaboration with Lotus Racing of Great Britain, and perhaps because it was hand-crafted by the women at Mercruiser Division of the Mercury Marine plant in Stillwater, Oklahoma, it was destined to become the strongest thump in ³The Heartbeat of America². The last of those amazing engines were pre-built in 1993 for installation in the 1994 and ¹95 model year ZR-1s. Yet, despite their age, LT-5 equipped Corvettes are thus far the fastest, mass-produced distance-racers ever to appear on the planet.

The reason for the ZR-1¹s uncontested dominance at marathoning is that even the least potent of the LT-5 engines (375 hp) were designed to safely propel a Corvette to 180 mph, with absolutely no modifications, and still meet all EPA emissions and fuel-economy standards. On its first attempt, a 1990 model ZR-1 broke the world¹s record for covering the most ground in 24-hours. It ran all day and and all night, averaging almost 176 mph, including gas stops!

With the new 24-hour World Speed Record now in the bag, the VERY SAME CAR kept lapping the same eight-mile test track in Texas, until it had set a new World Speed Record for 5000 miles, averaging almost 174 mph! Before this same ZR-1 finally pulled off that track, it ran two victory laps at over 190 mph, and ³America¹s Sportscar² owned TEN new International and World Records.

ZR-1 owners didn¹t get a gold medal, but beginning with the 1991 model, each car sported a tiny decal on the driver¹s side of the hatch glass, attesting to the ZR-1¹s new bragging rights; and by 1993, engineers had teased another 30 horsepower out of the bullet-proof engine. A few ZR-1s, whose owners tweaked the LT-5 beyond the factory¹s final 405 hp rating, have documented speeds in excess of 200 mph, yet they remain fully tractable for daily driving. Very few licenseable cars in the world, at any price, can reach such speeds in the first place, and fewer, still, are suitable for general transportation.

With a roll cage, one racing seat, open exhaust, an EDS telemetry system, and a 48 gallon fuel cell, the record-breaking Corvette was by no means a street car, but it was unquestionably a production car, using its officially specified production engine. The prospect of succeeding with that innocent combination had been so laughable at the time that the press wasn¹t even officially invited to watch. Nobody in over 50 years had beaten the 24-hour speed record -- even when using imaginative combinations of exotic racing engines and purpose-built chassis. How could a mere production-class Corvette succeed where unlimiteds had repeatedly failed?

Consider that the 175-180 mph speed range easily achieved by even the early, 375 hp, ZR-1 is comparable to current race averages in today¹s NASCAR events, where much lighter cars use the same size engine as the Corvette (5.7 liters or 350 cubic inches). Recall how many of those highly modified, NASCAR engines fail after less than 500 miles, and then ponder how the Corvette¹s LT-5 engine ran at the very same speeds for the equivalent of TEN Daytona 500s -- BACK-TO-BACK! That¹s a level of durability unprecedented in the automotive industry, a feat which has yet to be equaled by any production car, anywhere.

So it¹s not only that the ZR-1 is one of the few stock cars in the world that can comfortably run 180 mph; it¹s the fact that this car can do so, not just for hundreds, but for THOUSANDS of miles at a time! THAT¹S what¹s impressive. Yet in calmer moments it could deliver an amazing 28 mpg at 65 mph, while displaying world-class cornering, braking and acceleration to complement its awesome highway speed. That was enough ³all-around² superiority in performance for the media to dub the ZR-1 ³King of the Hill,² world-wide -- a reputation it successfully defended through the end of its production.

Certainly there were a few exotic street machines which could outrun a ZR-1, even during its hey-day -- but they could only do so for short distances. And, given the growing popularity of turbos and superchargers (the LT-5 required neither), there will likely be a much more impressive crop of sprinters wowing enthusiasts in this new century. But, the Dodge Viper excepted, from 1990 until the end of the last century, no such exotics were produced in quantities greater than a few hundred, and most of them numbered less than a handful. Even the few competitors which moved from prototype to limited-production, cost from twice to TWENTY-TIMES as much as the ZR-1¹s already hefty 66-thousand-dollar sticker, and still they couldn¹t keep up with the Corvette over long distances. The Porsche team admitted their 962, although faster, wasn¹t durable enough to last that long.

The sole, mass-produced, ZR-1 challenger in the 20th century was the Viper -- and despite having a much larger engine, and no concessions to refinement, it still failed to equal the Corvette¹s highway speed until a year after the ZR-1 was out of production. Today¹s 21st century Vipers, with a 150-cubic-inch-larger engine than the LT-5 ³small block², will certainly exceed an aging ZR-1¹s 180 mph top speed. But none of those 500 hp monsters have dared attempt the Corvette¹s 1990 marathon run, and neither have Porsche, Ferrari, BMW, or Lamborghini. Between 1966 and 1988, Ford, Mercedes and Audi at least tried -- but they all failed.

It¹s only in the 21st Century that the ZR-1 has seen its decade-old world records begin to fall -- but NOT to production cars. Except for the ZR-1, no automobile available to the public has EVER performed that well. In fact, the car that the ZR-1 beat in order to set those records was a one-off, hand-built racer, powered by an aircraft engine! Its driver, whose long-standing marathon record the Corvette thumped by a whopping 15 mph, was Ab Jenkins. I know the name because it¹s shared by my great-great-grandfather. And, as one would logically expect, the 21st century cars that have since broken the Corvette¹s marathon records are also prototypes, with their chassis never to see a showroom, let alone mass-production.

So it¹s very unlikely that the world will ever again see a production package accomplish such a feat. And even if another licenseable car does someday go that fast, for that long, the odds are against its ever being mass-marketed for thousands of happy enthusiasts. The Corvette ZR-1¹s achievement is thus a singular and enduring benchmark -- the high point in the first century of automotive history -- certifiably the only mass-produced car that, even with gas stops, could average over 175 mph all day and all night.

The heavy, elegant, ZR-1 could not only travel coast-to-coast distances faster than most private planes can fly them, it could do so with more amenities -- six-way adjustable leather seats, Bose stereo, air-conditioning, electrically adjustable suspension, F-16-style gold-reflective windshield, and monster brakes. Besides, the Corvette offered owners sleeker lines than anything propeller-powered -- except maybe the Mercruiser race boats sharing its engine¹s production facility. Odd, when you ponder it, that the engines of the fastest Corvettes ever sold to the public were designed in England and built by an American boat company! That eccentricity alone gives the 1990-1995 Corvette ZR-1 a unique bloodline -- a pedigree befitting the fastest production car of its time.

After fifteen years, the world has yet to mass-produce a marathoner which has proved itself the ZR-1¹s equal, but we can hope. The two-generation-newer C-6 Corvette, due soon at Chevrolet dealerships, is reputed to be even faster than the ZR-1; but GM hasn¹t yet shown the C6 can average 175 mph for the first 5000 miles of its warranty. And even if it can, the marathon records firmly held by the Corvette ZR-1 through the turn of the last century may now, by experimental prototypes, have been pushed out of reach for any production car -- let alone a mass-marketed Chevy.

But, for one brief, shining moment, the certified ³King of the Hill² could be driven out of an American showroom and onto a public highway, confidently assuring its pilot that nothing sold elsewhere at any price could match its pace and still go the distance. Were there an Olympics for cars, the indomitable ZR-1 would still be wearing gold. She done us proud.

Reproduced with permission.