Mach number temperature generally decreases with increasing altitude between sea level and , the speed of sound also decreases. For example, the standard atmosphere model lapses temperature to at altitude, with a corresponding speed of sound (Mach1) of , 86.7% of the sea level value. While the terms "subsonic" and "supersonic", in the purest sense, refer to speeds below and above the local speed of sound respectively, aerodynamicists often use the same terms to talk about particular ranges of Mach values. This occurs because of the presence of a "transonic regime" around M = 1 where approximations of the Navier-Stokes equations used
Ford Mustang Mach 1 Lincoln Aviator, and the 2003–2009 Australian Boss 5.4 L V8s (see Ford of Australia Boss 5.4 L), the engine also has intake camshafts sourced from Lincoln's 5.4 Liter "InTech" V8 to provide more mid-range torque. The Mach 1 engine had a 10.1:1 compression ratio in contrast to the 1999 and 2001 Cobra's 9.85:1, and the Mach 1 was equipped with a Windsor Aluminum Plant or WAP block unique from the Teksid aluminium blocks used in the 1996–1999 Cobras. The Mach 1 also featured a relatively high redline of 6,800 rpm (5-speed cars) and fuel cut off at 7,050 rpm "or