In the early 1960s he began working on the Coventry Climax Formula 1 engine, which was used at the time by Jack Brabham.
In 1980, Judd was hired by Honda to develop an engine for the company's return to Formula Two in association with Ron Tauranac's Ralt team.
Judd and his company came back to F1 in the 1988 season supplying engines for Williams, Ligier and March.
[4] In 1991 Judd struck a deal with Scuderia Italia to supply V10 engines for a Dallara-designed car.
In 2004, Judd's collaboration with Ray Mallock Ltd. earned the XV675 one of its few successes, winning the LMP2 class at the 2005 24 Hours of Le Mans.