Question: Who won 18 races driving Watson cars and an American race driver with 26 victories in top echelon open-wheel racing?

full_context: Document 1: 1964 USAC Championship Car season: The 1964 USAC Championship Car season consisted of 13 races, beginning in Avondale, Arizona on March 22 and concluding at the same location on November 22. There was also one non-championship event at Pikes Peak, Colorado. The USAC National Champion and Indianapolis 500 winner was A. J. Foyt. At Indianapolis in the 500 miles race Eddie Sachs and Dave MacDonald were killed during lap 2 of the race; Sachs was 37 years old, and MacDonald was 27. In the Tony Bettenhausen Memorial at Springfield, Bill Horstmeyer died during the race; he was 34 years old. In November, five days after the season ended, Bobby Marshman died in a testing accident at Phoenix; he was 28 years old.
Document 2: Bobby Unser: Robert William "Bobby" Unser (born February 20, 1934) is an American former automobile racer. He is the brother of Al Unser, Jerry Unser and Louis Unser, the father of Robby Unser, and the uncle of Al Unser, Jr. and Johnny Unser. He is one of ten drivers to win the Indianapolis 500 three or more times, and one of only two (followed by Rick Mears) to have won the 500 in three different decades (1968, 75, 81). Bobby has also been a spokesman and advocate of many commercial products.
Document 3: A. J. Watson: A. J. Watson (May 8, 1924 – May 12, 2014) was a car builder and chief mechanic from 1949 through 1984 in the Indianapolis 500, winning the race six times as a car builder. Rodger Ward won 18 races driving Watson cars.
Document 4: Wolf WR1: The Wolf WR1 was a Formula One car built for the 1977 season by the Walter Wolf Racing team. Four examples of the car were produced. The first, completed well before the start of the season, was the WR1. Another two identical cars were built: WR2, finished ahead of the first race; and WR3, ready in March 1977. At the end of the season, a fourth car, WR4, was produced with slight adjustments, and WR1 was remodeled in similar fashion for . The original car was driven exclusively by South African future 1979 World Champion Jody Scheckter in 1977. WR3 and WR4 were also driven by fellow future World Champion Keke Rosberg in the 1978 season.
Document 5: Rodger Ward: Rodger M. Ward (January 10, 1921 – July 5, 2004) was a WWII P-38 aviator in the United States Air Force, and an American race driver with 26 victories in top echelon open-wheel racing in North America, two Indianapolis 500 victories, and two USAC National Championships, who conceived the classic tri-oval design and layout of Pocono International Raceway, modeled after his three favorite signature turns, at Trenton, Indianapolis and Milwaukee.
Document 6: IROC I: The inaugural International Race of Champions was held at two tracks over two weekends in 1973 and 1974. The first three races were held October 27 and 28 at Riverside International Raceway and the final race was held on the Daytona International Speedway road course on February 14, 1974. Champion Mark Donohue won $54000 for his efforts and the championship was determined by prize money rather than points. The races were contested in Porsche Carrera RSR race cars. This was the only IROC to be contested entirely on road courses. Only the top 6 finishing drivers competed in all four races.
Document 7: Formula One drivers from the United States: There have been many Formula One drivers from the United States including two World Drivers' Championship winners, Mario Andretti and Phil Hill. Andretti is the most successful American Formula One driver having won 12 races, and only Eddie Cheever has started more grands prix. While many drivers from the United States have competed in Formula One, many of them are no longer counted in the sport's statistics because they only competed in the Indianapolis 500, which was at the time seen as part of the World Championship but rarely included any other Formula One drivers.
Document 8: 1951 Australian Grand Prix: It was the sixteenth Australian Grand Prix and the last to feature a handicap start which saw the slower cars starting ahead of the faster cars according to handicap allowance. The first car over the line was the MG TC special of South Australian Steve Tillett. The Australian Grand Prix title was however to be awarded to the driver setting the fastest outright time, regardless of handicap. The scratch race was won by Warwick Pratley driving a George Reed built Flathead Ford V8 powered racing car. It would be the last Australian Grand Prix victory by an Australian built car until Frank Matich won the 1971 race at the wheel of a Matich A50. Pratley started the race ten minutes and thirty seconds behind the first car to start the race, the Morgan of Colin Uphill. Pratley won the race by 96 seconds over the Delahaye of Dick Bland. Both Tillett and Pratley were awarded Commonwealth Jubilee Trophies for their victories in what was effectively two races in one.
Document 9: Hersham and Walton Motors: Hersham and Walton Motors (HWM) is the world's longest established Aston Martin business (having acquired the franchise in 1951) and is well known as a racing car constructor. As a constructor, it is best known for its involvement in Formula Two from 1950 to 1953 and Formula One in 1954. When HWM owners George Abecassis and John Heath went racing together from 1946 and in 1948 they built a streamlined sports racing car on the chassis of a Sports Alta, and thus embarked upon the construction of racing cars and racing sports cars at their motor works in Walton-on-Thames, England. The 1948 car gave them encouraging results and so new car, this time called an HW-Alta, was constructed and raced in 1949; this car was sufficiently successful to convince the partners to embark upon building a full team of cars for the 1950 Formula Two season of British and continental events: these cars were known as HWMs.
Document 10: Famoso Raceway: The Famoso Raceway dragstrip is located north of Bakersfield, California, and is known historically as the home to the annual March Meet, also known as the U.S. Fuel and Gas Championships. The strip, located on Famoso Road between Highway 99 and Highway 65 east of the Highway 99 and Highway 46 interchange, was originally built in World War II as an auxiliary training base for the nearby Army Air Corps training base at Shafter's Minter Field. After World War II, the Army abandoned the field. It was in the 1950s that an aspiring group of drag racing pioneers from the Bakersfield area, the Bakersfield Smokers, purchased the strip and made the necessary adjustments to allow for drag racing. The Famoso Raceway hosted the first ever March Meet in 1959 and it helped establish the fledgling National Hot Rod Association's (NHRA) legitimacy.
Document 11: List of USAC Championship Car seasons: From 1956 to 1978, USAC Championship Car seasons featured the top teams and drivers in U.S. open-wheel racing. Until 1971, the Championship contained road courses, ovals, dirt courses, and, on occasion, a hill climb. Thereafter, the schedule consisted mainly of paved ovals. In 1979, the majority of car owners left USAC to race in the Indy Car World Series, sanctioned by the Sports Car Club of America and CART. This led to a decline in the number of events in the schedule, and by the 1984-85 season, the Championship comprised only one race, the Indianapolis 500. The era of USAC Championship Cars concluded with the formation of the Indy Racing League (IRL) in 1995, which was sanctioned by USAC until June 1997 when the IRL assumed officiating duties after the controversial finish of the 81st Indianapolis 500 and the scoring mistake that marred the following event. The most successful driver in USAC Championship Car history was A. J. Foyt with seven National Championships and four Indianapolis 500 victories. Foyt competed in every season from 1957 to 1992-93.
Document 12: Al Unser: Alfred "Al" Unser (born May 29, 1939) is an American automobile racing driver, the younger brother of fellow racing drivers Jerry and Bobby Unser, and father of Al Unser Jr.. Now retired, he is the second of three men to have won the Indianapolis 500-Mile Race four times, the fourth of five to have won the race in consecutive years, and won the National Championship in 1970, 1983, and 1985. He is the only person to have both a sibling (Bobby) and child (Al Jr.) as fellow Indy 500 winners. Al's nephews Johnny and Robby Unser have also competed in that race.
Document 13: Cooper Car Company: The Cooper Car Company is a car manufacturer founded in December 1947 by Charles Cooper and his son John Cooper. Together with John's boyhood friend, Eric Brandon, they began by building racing cars in Charles's small garage in Surbiton, Surrey, England, in 1946. Through the 1950s and early 1960s they reached motor racing's highest levels as their rear-engined, single-seat cars altered the face of Formula One and the Indianapolis 500, and their dominated rally racing. Due in part to Cooper's legacy, Great Britain remains the home of a thriving racing industry, and the Cooper name lives on in the Cooper versions of the Mini production cars that are still built in England, but are now owned and marketed by BMW.
Document 14: IROC XXI: The twenty-first season of the International Race of Champions started on February 17, 1997. The series used identically prepared Pontiac Firebird Trans Am race cars, and contested races at Daytona International Speedway, Charlotte Motor Speedway, California Speedway, and Michigan International Speedway. Mark Martin won the IROC championship, his second straight and third in four seasons.
Document 15: A. J. Foyt IV: Anthony Joseph "A. J." Foyt IV (born May 25, 1984) is an American race car driver and also is a scouting assistant for the Indianapolis Colts. He competed in the IndyCar Series and briefly in the NASCAR Nationwide Series, then called the Busch Series. He is the grandson of A. J. Foyt.
ground_truth: Rodger Ward