Ford sold only 2,501 Mustang Mach 1s equipped with the R-Code Cobra Jet in 1970. This red example is a one-of-one by options combo.

However, as the Boss 429 engine was homologated in the Mustang, Ford used it in NASCAR until 1974 with other platforms. In 1971, Chrysler's 426 Hemi was under the watchful eye of NASCAR officials.