Per Wikipedia, the fountain of periodically guilt-ridden knowledge due to your lack of quarterly donations, the Boss 429 Mustang is a high performance Ford Mustang variant that was offered by Ford from 1969 to 1970. The Boss 429 is recognized as being among some of the most rare and highly valued muscle cars to date. In total there were 1358 original Boss 429s made. The cars were advertised at 375 bhp and 450 lb⋅ft of torque. The manufacturers and dealers only listed 375 bhp because of legal issues and rising insurance costs so customers would be lured into buying these cars without the stiff fees from an insurance company, though no manufacturer has ever stated this to be true, to prevent possible lawsuits.
Sales started to drop off for the 1970 Boss 429 Mustangs and with higher production costs, gas costs, and other internal Ford problems, it was decided that 1970 would be the final year. Today, these cars are highly sought. As of 2008, auctions on eBay and at Barrett-Jackson have brought bids of over $375,000. In 2013 a black 1969 Ford Mustang Boss 429 Fastback (unrestored) sold for $417,000 at Mecum Auctions in Kissimmee, Florida. In 2016 a restored black 1969 Boss 429 sold for $500,000 at a Barrett-Jackson auction in Palm Beach, Florida.