Engine-swapped classic Mopar muscle car was originally equipped with a 440 cu-in, 7.2-liter V8
July 8, 2024 at 14:45
- There’s a supercharged, Viper V10-powered Plymouth GTX up for auction on Bring a Trailer.
- Classic 1969 muscle coupe also has methanol injection, a six-speed manual transmission and Viper bucket seats.
- The GTX came standard with a 375 hp, 440 cu-in V8 in 1969, with the 425 hp, 426 Hemi a costly optional extra.
Mopar fans have been dropping modern Hemi and Hellcat V8s into classic muscle cars for years, but eight cylinders wasn’t enough for a previous owner of this vintage Plymouth GTX, so he upped the piston count to ten.
And he did it while keeping true to the coupe’s Chrysler roots, stuffing an SRT-10 Viper V10 mill between the shock towers – and then throwing on a supercharger for good measure as part of a wild build that took place in 2010.
Related: Viper V10-Powered Motorcycle With 500 HP Is A True Monster On Two Wheels
The auction listing on Bring a Trailer doesn’t say how much power the car makes, but Dodge listed a stock, third-gen ZB I Viper roadster as making 500 hp (507 PS) and 525 lb-ft (712 Nm) when new, and this GTX’s Paxton supercharger, methanol injection and other upgrades must surely push the power deep into the 700-horse category.
Whatever it makes, the GTX is certainly faster and more powerful than when it left the factory in 1969, and those things weren’t exactly lacking in urge the year Armstrong set foot on the moon.
A more upmarket take on Plymouth’s Road Runner, the GTX skipped the Runner’s base 335 hp (340 PS) 383 cu-in (6.3-liter) liter V8 and went straight to the 375 hp (380 PS) 440 (7.2) that could deliver 6.8-second zero to 60 mph (97 kmh) times.
The legendary 426 (7.0-liter) Hemi was a 425 hp (430 PS) option and mid-year Plymouth added a triple-carb Six Pack 440 that made 390 hp (396 PS). Even allowing for the different way ‘gross’ power was calculated back then, there was still plenty of it available.
But none of those ol’ time motors came backed by a six-speed manual transmission like this one does, courtesy of the same Viper that donated the engine and bucket seats. And they definitely didn’t have Wilwood cross-drilled discs, six-piston calipers and sticky Michelin radials, though the 18-inch wheels look like up-sized versions of the original 15-inch Magnum 500 rims it would have worn.
The seller has promised to add some videos to the auction listing, and I’ll be interested to see them, or more specifically hear them, because I love the noise of a good V8 but I’ve driven a few Vipers over the years and always thought Dodge’s V10 sounded awful: like a tugboat at idle and not much more special on the move.
Maybe this one will be different. It certainly is different from the usual muscle restomod, and although the build was done years ago, it still looks great. If you agree you can check out the full listing here.
