Gordon Murray insisted that the engine for this car be naturally aspirated to increase reliability and driver control. Turbochargers and superchargers increase power but they increase complexity and can decrease reliability as well as introducing an additional aspect of latency and loss of feedback, the ability of the driver to maintain maximum control of the engine is thus decreased.
Murray initially approached Honda for a powerplant with 550 bhp (410 kW; 560 PS), 600 mm (23.6 in) block length and a total weight of 250 kg (551 lb), it should be derived from the Formula One powerplant in the then-dominating McLaren/Honda cars. When Honda refused, Isuzu, then planning an entry into Formula One, had a 3.5 V12 engine being tested in a Lotus chassis. The company was very interested in having the engine fitted into the F1. However, the designers wanted an engine with a proven design and a racing pedigree.
The interior of the Saleen S7 was designed to be both luxurious and functional. Leather appears throughout the cabin, with aluminum accents, and the S7 comes with a set of custom-fit luggage. Because of the car's mid-engine layout, it has two trunks, front and rear. Other features include an LCD monitor, rear-view camera, quick-release steering-wheel and a 240 mile per hour (386 km/h) speedometer