Following regulatory changes by the Automobile Club de l'Ouest that eliminated the LMP900 and LMP675 classes in favour of the new LMP1 and LMP2 categories, existing Lola chassis were rendered non-compliant ahead of the 2007 implementation deadline. This prompted Lola to develop an entirely new car meeting the LMP2 specification.
The B05/40 can be considered an evolution of the MG-Lola EX257, also known as the Lola B01/60, with many mechanical and aerodynamic elements shared between the two cars. However, significant dimensional differences exist — notably the front overhang measuring 1,000 mm on the B05/40 compared to 810 mm on the EX257 — making the fenders bespoke to the newer car. The nose is raised in a similar fashion to the EX257 but lacks an opening grille at the tip; instead, two large NACA ducts are positioned on either side of the nose. Behind the cockpit, twin rollover hoops replaced the single hoop of earlier designs, as mandated by updated regulations. The engine air intake sits in a nacelle between these hoops, while turbocharged variants use a large duct mounted to the left of the cockpit.
Because the B05/40 was designed as a customer chassis for privateers, no standard engine was specified. The car accepted a wide variety of powerplants, including Nicholson-McLaren V8s, Judd V8s, Zytek V8s, Acura V8s, AER turbocharged inline-four units, and Mazda turbocharged inline-four engines.
Lola continually refined the B05/40 from 2005 onwards, introducing successive aerodynamic bodywork upgrades. In late 2006, a new chassis built for Fernández Racing's Acura project incorporated incremental improvements, leading Lola to designate it the B06/40. For the 2007 season Lola unveiled more substantial updates adopted by nearly all B05/40 customers, including a redesigned front end that replaced the twin NACA ducts with a single central nose opening. Despite this shared upgrade package, individual teams applied differing nomenclature, with B05/40, B06/40, and B07/40 all used depending on the chassis.
A further notable variant was operated by Ray Mallock Ltd. under the name MG EX264. This car was approximately 90 percent B05/40 in construction and was later upgraded with the 2007 bodywork while retaining the EX264 designation.
In the B05/40's debut season, Intersport Racing ran a single car in the American Le Mans Series while Chamberlain-Synergy Motorsport, Lista Racing, Ray Mallock Ltd., and Binnie Motorsports competed in the Le Mans Endurance Series. Intersport dominated the ALMS LMP2 class, claiming the championship with five victories over the season. In the LMES, Chamberlain-Synergy took the LMP2 title, with Ray Mallock finishing second and Horag fourth, each team claiming one win. At the 24 Hours of Le Mans, Ray Mallock took the LMP2 class victory, with Intersport and Chamberlain-Synergy also competing.
All B05/40 teams returned for 2006, though Chamberlain-Synergy's entry was taken over mid-season by ASM Team Racing for Portugal. In the ALMS, Intersport's LMP2 title defence was thwarted by the arrival of the Porsche RS Spyder, despite the team recording three wins. The LMS told a similar story, with Barazi-Epsilon's Courage Competition machine edging the Ray Mallock EX264, which managed one win. Chamberlain-Synergy scored three wins before the ownership change split their championship points. At Le Mans, Ray Mallock claimed another LMP2 victory, with Intersport, Binnie, and Chamberlain-Synergy all fielding entries.
For 2007, Intersport stepped up to the LMP1 class with a new chassis, while Fernández Racing joined with their upgraded Acura-powered B05/40. B-K Motorsports purchased a new B05/40 running Mazda turbo power, replacing a previous Courage chassis. Ray Mallock, Horag, Binnie, and ASM Team Racing for Portugal all continued in the Le Mans Series, each running with the 2007 aerodynamic upgrade package.
The B05/40 established itself as one of the most successful privateer LMP2 platforms of its era, capturing multiple class championships across both the ALMS and LMS in its debut season and remaining competitive through successive update cycles. Its modular engine compatibility made it accessible to teams using a range of power sources, and the lineage of continuous upgrades — B05/40 through B07/40 — demonstrated Lola's ability to evolve a customer racing product across multiple regulatory seasons.