Connaught's original ambition for the Type B was to build a streamlined Grand Prix car using the 2.5-litre Coventry Climax FPE "Godiva" engine. When that engine project was abandoned, Connaught turned instead to the Alta straight-four unit. The intended streamlined bodywork was also dropped after drivers reported similar visibility and placement difficulties to those experienced with the Mercedes-Benz W196 streamliner — they could not accurately judge the car's position at the apex of corners. More conventional close-fitting bodywork replaced it.
Seven Type B chassis were built between 1954 and 1958. All used a conventional tubular space frame with wishbone and torsion bar independent front suspension and a De Dion axle at the rear. Disc brakes were fitted at all four corners — a relatively advanced specification for the period. The Alta 2.5-litre four-cylinder engine produced 250 brake horsepower, transmitted through a four-speed preselector gearbox.
The Type B made its competitive debut at the 1955 Glover Trophy, where Tony Rolt qualified fifth but retired early with fuel pump failure. Through the 1955 season the car struggled to keep pace with the dominant Maserati 250F and the emerging Vanwall challenge. At the 1955 British Grand Prix, all five Connaught entries failed to finish.
Team owner Kenneth McAlpine was considering winding up the operation entirely when the prospect of substantial starting money from the organisers of the 1955 Syracuse Grand Prix in Sicily persuaded him to enter two cars, driven by Tony Brooks and Les Leston. In a result that astonished the paddock, Brooks won the race by fifty seconds from the works Maserati 250F of Luigi Musso. It was a genuinely historic moment — the first victory for a British car on a Continental European circuit in thirty-one years.
Syracuse, however, proved to be the exception. Cash constraints prevented Connaught from running a sustained World Championship programme, and across just five World Championship races over the following three seasons, the team's best result was a third place for Ron Flockhart at the 1956 Italian Grand Prix. In British national events the Type B was marginally more effective, with Archie Scott Brown winning the 1956 BRSCC Formula 1 Race and Stuart Lewis-Evans taking the 1957 Glover Trophy.
The final World Championship appearance of the Type B came at the 1958 British Grand Prix, by which point the team was being run by a young Bernie Ecclestone. Both cars retired from that race, and Connaught withdrew from racing shortly afterwards.
The Connaught Type B is best remembered for the Syracuse result, which helped demonstrate that British manufacturers were capable of competing with — and beating — the established Italian constructors on their own soil. That symbolic importance was significant in the context of what was about to happen in Formula One: within a few years, British constructors would come to dominate the sport. The Type B is also a footnote in the career of Bernie Ecclestone, who ran the team in its final season before eventually finding his way to a far larger role in the governance of Formula One.