There were two so-called “quarter horses,” or as Ford executives called it, the Composite Mustang. Both terms were apt: Ford had Kar Kraft start with a pair of Boss 429 Mustangs, add Mercury Cougar dashboards, fit 1969 Shelby G.T.500 front sheetmetal, close off the hoodscoops and mount a regular Mustang galloping horse to the center of the grille. Ostensibly built as a potential mid-year 1970 replacement for both the Boss 429 and the proliferation of Shelby Mustangs (Carroll Shelby asked Ford to discontinue the Shelby Mustang program after 1969, and contemporary critics were bashing Ford’s teeth in for having so many performance models), the program never got off the ground. The Shelby G.T.500 sold so poorly in 1969 that the leftover models were re-titled as 1970s, thus destroying any justification for the Composite Mustang’s production.
At least one of the two, possibly both, were subsequently fitted with 429 Super Cobra Jet V-8s. Both remain in the hands of collectors.