Robert John Cahill, who started working at Chrysler in 1936 (doing concurrent coursework at the Chrysler Institute of Engineering ), went on to become an instrumental part of the company's racing efforts. One of his most famous initiatives was the 426 Hemi; he wrote the official Product Planning letter to Engineering which kicked off the project, and brought in airflow expert Harry Weslake to consult on the highly effective head design. Along with Bob Rodger, Cahill also wrote the 1965 memo which led to the creation of the Street Hemi. He was also a force behind the Hyper-Pak powered slant six Valiants which took first, second, and third place in the first (and only) compact-car NASCAR race of 1959.

Born May 10, 1915, Bob Cahill was a leading modeler before joining Chrysler, winning his first contest in 1929 with a functional airplane model; he has been inducted into the Society of Antique Modelers Hall of Fame. After retiring in 1975, Cahill moved to the U.S. Virgin Islands, bought, repaired, and sailed a 36-foot sailboat, and later moved to California, building and flying a plane. Eventually he moved to Charlottesville, Virginia.

John Wehrly, formerly Dodge Engineering Motorsports Manager, wrote, "He was one of my bosses in the early 1970s and always treated me with a great deal of respect. ... He never 'elevated' himself, just because he was the boss. He was a thoughtful and talented engineer and was steps ahead of our competition, whether it was in racing or a fuel economy contest. When the SRT Neon came out, Bob was, at 90 or so, trying to get a 'good deal' on the Neon, not considering his age as an issue. Bob always tried to stay in contact with the guys he worked with — right up to when he died. I feel very privileged and honored to have know and worked with Bob."

Bob Cahill died on November 14th in Little Rock, Arkansas, at the age of 96. He had a daughter, Judith, two brothers, and three grandchildren. Services were at Little Rock Funeral Home.