HomeAutoHunter1971 Plymouth GTX-R Melds the Past with the Present

1971 Plymouth GTX-R Melds the Past with the Present

Horsepower Northwest ditches the 440 for a Viper V10


The Plymouth GTX was perhaps THE true heavyweight in the muscle car world. From 1967-71, the mighty Mopar came equipped with a standard 440 Super Commando when many cars came standard with engines 40 cubic-inches less. Horsepower was 375 (370 in 1971), which no manufacturer could match except with optional engines. That’s why, in advertisements, the GTX was called “The Boss.” And if you encountered a pesky Brand X car on the local pike, there always was the 426 Hemi.

So, what would happen if you took the GTX and brought it to contemporary standards? Horsepower Northwest has the answer. They took a 1971 GTX (which was redesigned that year) and stuffed a 630-horsepower 8.4-liter Viper V10 between the front wheels and paired it with a TREMEC T56 Magnum six-speed manual. Other modern tweaks include a fully welded chassis with Baer disc brakes on all four corners, plus a set of custom satin bronze Boze Alloy wheels with 18-inchers up front and 19-inchers out back.

All this is wrapped up in classic Mopar Fuselage goodness, including throwback F8 green paint complemented by a tan and black interior. Horsepower Northwest calls it “GTX-R.” Drooling yet? If not, you will once you’re done with the above AutoHunter Cinema video.

Diego Rosenberg
Diego Rosenberg
Lead Writer Diego Rosenberg is a native of Wilmington, Delaware and Princeton, New Jersey, giving him plenty of exposure to the charms of Carlisle and Englishtown. Though his first love is Citroen, he fell for muscle cars after being seduced by 1950s finned flyers—in fact, he’s written two books on American muscle. But please don’t think there is a strong American bias because foreign weirdness is never far from his heart. With a penchant for underground music from the 1960-70s, Diego and his family reside in the Southwest.


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