The Saleen S7 is a limited-production, hand-built, high-performance American supercar developed jointly by Steve Saleen for the initial concept and direction, Hidden Creek Industries for resources and initial funding, Phil Frank for the body and interior CAD design and development, and Ray Mallock Ltd. for the chassis engineering. It was the only car produced by Saleen not based on an existing chassis. The S7 debuted on August 19, 2000 at the Monterey Historic Races. From 2000 until 2004, the S7 featured a Ford 427 big block, naturally aspirated V8 engine with 550 horsepower (410 kW). In 2005, the S7 was replaced by the S7 Twin Turbo, which featured a more powerful twin-turbo system that boosted engine power to 750 horsepower (760 PS/559 kW) and the top speed 248 mph (399 km/h).