There are lots of classic Mopar muscle cars on display at this week’s SEMA Show in Las Vegas, but none are as unique as the Ringbrothers’ 1972 AMC Javelin AMX, named “Defiant!” – including the exclamation point.

Although this customized Javelin has a unique enough exterior design to allow it to stand out at any car show, the thousand-horsepower Hellcat Hemi under the hood makes this one of the most powerful American Motors products we have ever seen.

The Ringbrothers (Jim and Mike Ring), from Spring Green, Wisconsin, have long admired the AMC Javelin AMX. So when Prestone came to them with the idea of a customized muscle car to celebrate the coolant brand’s 90 th anniversary, theylocated a donor car and began their work on Defiant!

This 1972 AMC Javelin AMX has a collection of carbon fiber body panels that cut weight and present a unique exterior design. The bulging hood, flared front fenders, and heavily sculpted front fascia make the Javelin AMX even more aggressive looking. This custom body package is finished off with the unique side-exit exhaust, huge rear spoiler, aftermarket wheels, a massive high performance brake system, and a low-riding stance (from a four-link suspension setup).

Even with “just” this exterior upgrade list, the Ringbrothers' 1972 AMC Javelin AMX would have been a showstopper at SEMA. They could have spruced up the factory 401 cubic inch V8 with some chrome and carbon fiber, and we would have all swooned over this car, simply because a massively-modified Javelin like this one is so rare. However, the Ring brothers wanted to make sure that this Mopar muscle car packed as much “go” as it does “show.”

To do that, the factory engine was replaced by a supercharged 6.2L Hellcat Hemi, but even then, 707 horsepower wasn’t enough for the Defiant! Javelin. With the help of a 4.5L Whipple supercharger and the supporting modifications, the output of this American Motors machine has been increased to over 1,000 horsepower.

When it comes to rare Mopar muscle cars, I'm not sure if it gets much cooler than a carbon fiber-bodied, Hellcat-powered 1972 AMC Javelin AMX; it could easily be argued that the Ringbrothers Defiant! Is the coolest custom AMC in existence.