1970 Mercury Cougar XR7 Convertible 428CJ Ram-Air Four-Speed Documented Ford Test Vehicle! Rarest and most stylish of all Ford and Mercury Muscle Cars! Here we have a car that is at the top of the list of rare and unusual Muscle Cars. Some call this 'The' ultimate Muscle Mercury, ultra-rare and with great documentation to match. This is a totally restored 1970 Mercury Cougar XR7 convertible equipped with the 428 Cobra Jet engine, the Ram-Air option, and best of all, a close ratio four-speed transmission. This particular is the FIRST 1970 Cougar convertible (XR7 or standard) built with a 428 CJ engine. They donÃ¢â‚¬™t get rarer than this, which is the most desirable engine-transmission option available. According to Kevin MartiÃ¢â‚¬™s database, only 37 cars were equipped with 428 CJ engines from the factory. Of these, 20 had automatics, and the remaining 17 got the four-speed. Only four of the four-speed cars had the Ram-Air option. This is one of those four, and may be the only one built with AC. The other options this car has are power steering, power brakes, console, and styled steel wheels. The story gets even better: This car is a DOCUMENTED Ford Test Vehicle. DSO (District Sales Office) 84, which means Home Office Reserve. Tes cars were supposedly crushed because they no longer could be warranted if sold. Here is one that got away! I found a pair of 1970 Illinois license plates in the car when I disassembled it. The plates have been restored and go with the car. Perhaps you can use them to track down the original owner.