Following the 1963 racing season, Wallace was hired by Lamborghini at the then-new factory in Sant'Agata Bolognese. Initially, his role was to assist in production of the 350GT as a mechanic and, in his words, "trouble-shooter". He was soon recognised at the factory as talented in vehicle evaluation and subsequently became the chief test driver for Lamborghini, a position which included duties as a road development engineer. The majority of Lamborghini testing at that time was conducted on public roads, including the autostrada and mountain roads, although cars were also run at tracks such as nearby Varano Circuit. During road tests, Wallace often engaged in informal competition with the Ferrari and Maserati test drivers, either directly or through timed runs such as the 105-mile distance between the Milan and Modena autostrada toll booths. In 1965, Wallace worked with Gianpaolo Dallara and Dallara's then-assistant Paolo Stanzani to develop the Lamborghini Miura. He conducted extensive road testing of Miura prototype and production cars, informing the development of Miura S and SV versions. He also participated in development of the 400GT, Islero, Urraco, Jarama, Espada, and most extensively, the Countach, including road-testing of the LP500 prototype. Wallace created three lightweight high-performance versions of Lamborghini road cars during his time at the manufacturer. Despite Ferruccio Lamborghini's reluctance to become involved with racing, Wallace believed Lamborghini production models had great competition potential and built these modified versions on his own initiative as both proof of concept exercises and test mules. The first and most well-known of these specials was the Miura P400 Jota. After creating the Jota, Wallace modified Jarama #10350 to create the Jarama "Bob," RS, or Rally. He performed many racing-oriented modifications to this car including a stiffened chassis, lighter body panels, modified aerodynamics, upgraded suspension, Miura wheels, and a reworked engine producing an estimated 380 bhp. The final Wallace special was the Urraco "Bob", created from the third Urraco pre-production prototype. The car was lightened, stiffened, and provided with aerodynamic enhancements, a roll cage, six-speed transaxle and a special "quattrovalvole" 3.0 litre V8 engine producing 310 bhp. This was the only one of the three factory-built Wallace Lamborghinis to actually race, in a single outing at Misano Circuit. Wallace left Lamborghini in 1975, following Ferruccio Lamborghini's sale of the company in 1974. Subsequently, Valentino Balboni took over as chief test driver.
Later life
Following his departure from Lamborghini, Wallace and his wife settled in Phoenix, Arizona. There he established an independent mechanic shop, Bob Wallace Cars, where he restored and maintained Ferrari and Lamborghini cars. Much of Wallace's work at this shop involved maintenance, restoration and race preparation for vintage Ferraris. Wallace died on 19 September 2013 at the age of 75.
