The 2007 Dodge Demon was a production-ready concept. Rear drive, six-speed manual, but just a 172-hp four-cylinder. An intercooled turbo would push it over the Fox Mustang’s V-8 output.

Saturday in 1981, Mick and Jo Wildin found themselves traveling through a dimension of time between sports car purity and modern comfort, a journey whose boundaries were that of 1970s devil-may-care ...