The Mustang Boss 429 is what you get when a carmaker needs to meet NASCAR regulations. Fewer than 1,400 were built between 1969 and 1970, making the Boss 429 a rare bird indeed.
Enjoying a big-dog reputation, the Boss 429 wasn’t a giant killer right out of the box. Its 429-cubic-inch V-8 engine delivered 375-horsepower, not shabby but dwarfed by others on this list.
What makes it truly notable is that it was basically hand-built. Because the engine wouldn’t fit in a standard Mustang without extensive modifications, Ford farmed out its assembly to Michigan-based Kar Kraft. In appearance, very little distinguished the Boss 429 other than a hood scoop and trunk-mounted spoiler.