Among the rarer late-Sixties Pony cars was Ford’s Mustang Boss 429. When a bright red, perfectly-restored example finds itself in Jay Leno’s garage for his eponymous web series this week, Leno’s beyond eager to drive it. But first, a quick history lesson on how this throaty muscle coupe came to be.

When Semon “Bunkie” Knudsen became Ford’s president following his departure from GM, Blue Oval engineers had been working on the Boss 429 engine for the Galaxie. Knudsen told them to scratch that and instead figure out a way to cram that massive NASCAR V8 into the Mustang. Carcraft, a Dearborn, MI, outfit that worked closely with Ford in the same vein as AMG worked with Mercedes-Benz, was responsible for getting that prodigious drivetrain in the ‘Stang, and oversaw the entire build of the 1969 and 1970 Boss 429s. Those models were underrated in terms of competitor power. Mopar Hemis were cranking out 420-plus horsepower; the Boss 429 had 375 and 450 lb-ft of twist.

Marcus Anghel, of AnghelRestorations.com, who oversaw the rebuild, says they were written off because they “were detuned for the street. There were issues with insurance and smog,” among other things. This car featured a smog pump, which Anghel points out after popping the hood to reveal a sparkling clean engine. Anghel indicates some of the mods Carcraft had to make to shoehorn that V8 in the smaller bay, such as moving the shock towers.