History doesn’t often fondly recall the 1970s when it comes to automotive performance. Just as the musclecar era of the ’60s seemed to be reaching its pinnacle at the turn of the decade, a confluence of government emissions mandates, insurance premiums, and skyrocketing fuel prices quickly changed the performance landscape in dramatic fashion.
Like many other performance icons of the era, the Corvette suffered tremendously from these changes, seeing a shift from big-blocks dishing out well in excess of 400 horsepower to anemic 350s barely able to doll out 165 hp as standard issue just five years later. Indeed the Malaise Era was rough for the Corvette, and high performance at large.
By the mid-1970s the Corvette, like the rest of the automotive world, found itself hamstrung by emissions regulations, fuel economy concerns and other factors that led to a steep decline in performance over just a few short years. 1975 served as a low point for Chevrolet’s sports car, with the standard 350 V8 offering just 165 horsepower. But for those with the means, pivoting from street performance to officially-sanctioned racing offered an alternative where serious capability still ruled the day. Image: GM
While it would have a profound change on vehicles designed and sold to the general public, within the realm of motorsport it was a different story, as none of those aforementioned issues applied to racing efforts. In an era when the Corvette was at its lowest, two brothers from Detroit named John and Burt Greenwood sought to take on the racing world with the Chevrolet’s sports car, and managed to alter Corvette race car design for the better in the process.
The Greenwood Story
John Greenwood was a guy who liked going fast. The son of GM exec, as a teenager John spent many a night street racing on Detroit’s Woodward Avenue in his coveted Satin Silver ‘64 Corvette. “I switched over to Corvettes fairly early, when I bought a silver 1964 – I was about 18 or 20 at that time,” Greenwood said in an interview posted on the Greenwood website. “I was one of the first to fit one of the early 427s. It took some modifications to the frame rail but the cars were lighter and the suspension was better. It was obvious that the car was a better platform.”
Though Greenwood had proven himself to be very competitive out on street and at local autocross events, his transition into officially-sanctioned road racing didn’t go as smoothly as one might have expected. After a disappointing 1968 season, Greenwood went back into the garage and focused on setting up the car around his driving style. His return to the track for 1969 would prove to be a very different story than that of the previous year, and he would take home the SCCA A-Production National championships back-to-back for the next two seasons. Image: Hemmings
John’s passion for performance and racing was intense. “I was kind of driving my parents crazy; I built the engines in the basement or the den and then carried them up through the house,” he recalled. “I just kept building them and racing them. I would tune my cars up every single night and go out and race about 150 miles.”
A few years later when the C3 debuted, John was immediately enamored and picked up a T-top coupe. He would be among the first to shoehorn one of GM’s most potent power plants into it. “I bought a 1968 Corvette and the first night I put an L88 into it,” Greenwood said.
While he had proven to be a force to be reckoned with on the street, Greenwood had yet to apply his talents the realm of proper motorsport. One day, his wife came across an ad in the grocery store for a parking lot autocross competition and dared Greenwood to enter. He obliged. “I won everything,” he quipped. “Then I went back the next week and did the same. There were some pretty fancy cars because a whole bunch of road racers showed up with trailered cars, but I won again. So, I figured that since I could win, this wasn’t a bad deal.”
Greenwood decided that this whole motorsport thing was worth a closer look, so he headed to Waterford Hills race track and enrolled in a road racing driver’s school. However, Greenwood’s introduction to wheel to wheel racing didn’t go as swimmingly as one might have expected. “I didn’t do so well,” he explained. “The guys instructing me did things differently than I was used to and I seemed to go backwards. There were women in Fiats beating me. I went through two sets of tires one weekend just trying to keep up.”
“I went away thinking that maybe this wasn’t for me,” Greenwood continued. “I thought about it that winter and, because I am a car setup person, I kind of figured out what I had to do. I guess this was also the same time that I formed my engine building company, Auto Research Engineering (ARE).”
Greenwood’s eventual success in SCCA racing would help him secure a major sponsorship deal with BF Goodrich. While the sponsorship support helped elevate his racing career substantially, the contract stipulated that he had to use the company’s new high performance street radials rather than the race slicks utilized by the rest of the field. This inherent disadvantage made it difficult for the Greenwood Corvettes to put the power down effectively. Image: Hemmings
When Greenwood returned for the 1969 season after spending some time dialing in his suspension setup and engine tune, the results that year proved to be quite different. “I did a lot of racing that year and I started setting records,” Greenwood explained. “In the next two years, I won the SCCA A-Production National Championships back-to-back. You know that a lot of the equation was the big engines. I had learned on Woodward Avenue that you don’t want to get left behind on the straight parts. It also goes without saying that through all of this I had full support from my brother Burt and I also had a good back-up driver in Jim Greendyke. ”
Greenwood’s victories in the SCCA would attract some attention to the fledgling race team. Zora Arkus-Duntov and engineer Gib Hufstader had been providing technical assistance to Corvette racing efforts on the sly for years at this point, and when Greenwood’s team shut down the heavily favored Owens Corning team (who had gone undefeated in the previous 22 races, a record at the time) at 1970 A-Production championship race at Road Atlanta, Zora and his crew took notice.
With BF Goodrich backing, the Greenwood team was able to bring their Corvettes to the international stage of motorsport, and after competing in endurance races like the 24 Hours of Daytona and the 12 Hours of Sebring, the team would take on Le Mans in 1972 and 1973. But the dominance Greenwood sought remained elusive, so as the contract with BF Goodrich neared its end, the team began to devise a new strategy for the 1974 season. Images: RM Sotheby's
So did some big-name sponsors, and when the Greenwood team inked a deal with BF Goodrich it gave them a chance to compete on the world stage in the FIA’s endurance racing classes. After stints in the 24 Hours of Daytona and the 12 Hours of Sebring, the team would take on Le Mans in 1972 and again in 1973. Though the cars were outgunned by the competition – due in part to the fact that they were contractually obligated to run BFG street radials while the rest of the field used race slicks – clocking 215 mph down the Mulsanne Straight proved that the Greenwood cars were indeed fast.
With the BF Goodrich contract near its end after the 1973 season, Greenwood and his team began to devise a strategy that would allow them to truly utilize the power the Corvette’s engine had on offer, and it involved a substantially wider tire in the rear. But to make it all that rubber fit under the fender, the body would need to undergo a substantial transformation.
Greenwood had a new strategy for the 1974 season. He went to Duntov with his idea for a wild new body design that could accommodate the massive rubber the Corvette would need in order to effectively put the power to the ground, and with the help of Randy Wittine from the GM design studio they put together some sketches and eventually a mockup of the new car.
Greenwood's struggle for traction with the BF Goodrich radials had set him down a path to find ways to put the warmed-over L88 427's prodigious power to the ground. With the help of Corvette engineer Zora Arkus-Duntov and Randy Wittine from the GM design studio they devised a new body design that could accommodate the massive race slicks Greenwood wanted to use while integrating functional aero into the expanded bodywork. They named it the widebody. Images: Russo and Steele
Dubbed the widebody, it was a dramatic departure from Corvette race cars of the past, and with its dramatically flared fenders and deeply sculpted bodywork, it both looked and performed unlike any Corvettes before it. Now with adequate grip on tap, the Corvette could effectively use all 750 horsepower that the modified L88 had to offer, and the integrated aerodynamics of the wide body package kept the car planted to the ground and stable at high speeds.
While the production-based Corvette had been choked to within an inch of its life by 1976, the rules that constrained street car design did not apply to IMSA racers. By then the Greenwood Corvettes were making in excess of 1000 horsepower thanks to a thoroughly massaged version of the L88 427 big block V8. Images: RM Sotheby's
With other domestic efforts bowing out of the IMSA series at the same time, the Greenwood team was left as the sole American entry to take on the Europeans, making the car’s star-spangled livery all the more fitting. The Greenwood Corvette brought the heat to the motorsport world at large, capturing the IMSA title that year, the Trans Am championship the following season, and securing numerous pole position qualifying runs and track records along the way. One of the cars was clocked at a hair-raising 236 mph down the back straight at Daytona during qualifying in 1975!
A few years later tube frame chassis designs would show up on the scene and the departure from production-based race cars was underway. But for a brief moment during a low point in production Corvette performance, John Greenwood and his team helped elevate the sports car’s status not only in motorsport but in the eyes of the world at large while simultaneously introducing a new innovative approach to race car design that is still in use to this day.
The Greenwood team’s wide body approach continues to see use in race car designs today. Image: RM Sotheby’s
Over the few years that the widebody was campaigned, Greenwood produced a handful of customer race cars configured in similar fashion to the cars the team was using. These few chassis, along with the cars built for the Greenwood team, have commanded figures approaching half a million dollars in recent auctions.
Though they weren't packing the brutal performance of the modified L88 427s used in the race cars, Greenwood did produce a small batch of widebody-style street cars on a made-to-order basis between 1975 and 1981. Images: Greenwood Corvettes
Additionally, a small batch of Greenwood-modified C3 street cars were also produced. Between 1975 and 1981, Greenwood built 43 custom examples based on five different distinct body styles that all borrowed from the widebody race car’s aesthetic. Though their performance was a far cry from their race car counterparts, the Greenwood C3 street cars brought some of the visual drama of the Greenwood racers to the streets of America and are considered collectors’ items today.