Ayrton Senna and Mika Häkkinen tested the car at both Silverstone and Estoril, with the first test taking place at Silverstone on 20 September. The modified MP4/8B, painted white with no sponsorship logos other than Goodyear, took three months to re-engineer and stretch in order to fit the longer and heavier engine (the V12 was badged as Chrysler for the McLaren tests). After first driving the car Senna suggested to the engine's designer, former long-time Ferrari engineer Mauro Forghieri, that it would be better with a less brutal top end and a much fatter mid-range. Forghieri, who had enormous respect for the triple World Champion and valued his opinion, made the requested changes. While the engine lost at the top end, the test engines gained some over the 1993 Lamborghini race engine, giving the V12 approximately , around more than the customer Ford V8 engines and almost on par with the most powerful engine of 1993, Renault's V10. This also gave the Lamborghini engine around more than the V12 used by Ferrari, the only other V12 in Formula One at the time. The resulting changes to the V12 reportedly made the MP4/8B more drivable and much faster than before, even faster than the race version. According to reports at the time, the combination of the MP4/8B and the Lamborghini V12 actually proved more stable and easier on tyres than the Ford powered MP4/8 race cars.