Unlike the Mustang, every first-generation Cougar was V-8-powered and could be had with Windsor, Cleveland, and FE engines with displacements from ranging from 289 to 428 cubic inches. Just about every Mustang V-8 option was available in the Cougar except the Boss 429, although two purpose-built drag racing Cougars were eventually fitted with the Hemi competitor. With no rare Boss 429 model to take the lead, the most valuable Cougar is the 1969 Eliminator with the 428/335hp Super Cobra Jet engine, which has an average #2 (Excellent) value of $149,000.

Ford marketed the original Mustang as a 1965 model, though Ford made several production changes to cars built after August 1964, by which time Ford had already sold 120,000. Hobbyists refer to early Mustangs as “1964½” models, while post-August cars are “late” 1965s. The Mustang launched with convertible and notchback body styles, with the fastback joining the lineup as a late ’65. A plethora of options enabled buyers to configure their Mustang as anything from an economical runabout to a weekend race car.  Total sales for the 1965 model (including “1964½” cars) was 681,000—nearly seven times Ford’s projections.