Chrysler built roughly 9,137 street Hemi cars between 1966 and 1971, and only a sliver of them left the factory as convertibles. The 1970 Dodge Coronet R/T Hemi convertible is widely considered the rarest of the bunch at just two built, with Hagerty pegging a top example near $1.3 million. A numbers-matching 1971 Hemi ‘Cuda convertible brought $3.5 million at Mecum in 2014. Read on for why the drop-tops are so scarce and what separates a real one from a clone.