This Reinforced 1971 Plymouth Road Runner Packs A V10 From A Viper

It has a six-speed manual, too.

Horsepower Northwest

“If you’re a Mopar guy, you own more than one Mopar.” That’s according to Aaron Porter, owner of Horsepower Northwest in Bremerton, Washington. In his line of work building and restoring vintage Mopar muscle cars, Aaron has seen his fair share of trade-for-labor deals. If a customer can’t afford the labor, he or she may offer a rusty parts car as a trade. Aaron is always willing to make a deal because one, he has the space, and two, you never know when a rusty rolling chassis will come in handy.

Aaron Porter

That was the case when a 1971 Plymouth B-body ended up in his shop’s parking lot. No engine or transmission, no fenders, no doors, and typical Swiss cheese floors and trunk. Yet this stripped out parts car became the platform for a build known simply as the GTX-R. This former 318ci base model Plymouth has been built around its new heart, a V10 engine out of a 2008 Dodge Viper, and a six-speed manual.

During an interview with Aaron, he was quick to mention that Viper engines are not easy to swap. They are long engines that require modifications to the engine bay to make them sit correctly. The GTX-R project started out as a request order from a client in London in 2018. However, by the time the car’s bodywork was done and the engine was fitted the client backed out of the deal. Aaron decided to finish the car because they were already knee-deep into it.

Aaron Porter

As mentioned, the GTX-R is built around the Viper engine. The radiator mount was moved forward, everything in the engine bay was lowered. This B-body muscle car has been given some serious gains to be able to handle the new performance. The entire body and frame of the car has been fully welded and fitted with tubular steel framing that’s been tucked under the bodywork. This muscle car will be able to carve an apex like Freddy Krueger on wheels when it’s done, thanks to a full RMS Reilly Motor Sports suspension, 8.75 rear end, and Baer disc brakes.

Aaron Porter

Graphic designer Abimelec Arellano did a fantastic job rendering what the finished product will look like. It will be a pro-touring Mopar. Aaron wanted the GTX-R to look as clean as possible—no SEMA showboating besides some gold wheels and fat low profile tires.

Horsepower Northwest has made a business out of saving rusty Mopar donor cars. They’ll take a basket case ’70 Cuda and drop in a 392 Hemi or Hellcat engine with modern suspension and disc brakes. As Aaron also says, “The rare Hemis are safe with collectors. Why build a clone with no creativity when you can build a better Mopar?”

You too can build the Mopar of your dreams. Or just call Aaron and he’ll do it for you.

Aaron Porter

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