Cuda Powered By A Mind-Bending 1,500hp Turbo 6.7-Liter Cummin…

Most diesel-swapped muscle cars look like a rushed compromise under the hood – pipes everywhere, nothing lining up. This Plymouth ‘Cuda is the exception, built by Weaver Customs with a compound-turbo 6.7-liter Cummins shaped to fit the factory engine bay like it was born there. The horsepower number is big, but the reported torque figure is the one that actually stops conversations at diesel meets.

Pop the hood on most diesel-swapped muscle cars and you get a rushed, hacked-together mess — pipes zip-tied where they don’t belong, a cowl hood bolted on to hide the ugliness underneath. This Plymouth ‘Cuda breaks that mold entirely, wearing a drivetrain that has no business fitting inside an E-body engine bay, let alone looking like it was born there. Builder Randy Weaver spent years solving a puzzle most shops wouldn’t attempt: shoehorning a compound-turbo diesel powerplant into a classic muscle car without sacrificing the factory-look fit and finish collectors expect. The number he landed on isn’t just impressive — it’s the kind of figure that makes seasoned engine builders ask him to repeat it. So what exactly is hiding under that hood, and how does a diesel truck engine end up making a vintage Mopar this violent?

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A Diesel Heart Nobody Saw Coming

The engine is a 6.7-liter Cummins inline-six, built by Weaver Customs and tuned by Gorilla Performance, and it wears the nickname “Torc” for good reason. On a 500-shot of nitrous, the combination reportedly puts down 1,500 rear-wheel horsepower — but the torque figure is the one that turns heads, said to top 3,000 lb-ft. Inside, the bottom end runs Carrillo rods and Mahle pistons, backed by a ported and polished cylinder head and a dual-fueler system feeding the injectors.

Twin Turbos and an 80-mm Statement

Up front sits an 80-mm BorgWarner turbo, big enough to see from across a parking lot, paired with a smaller 66-mm unit tucked in behind it. Together the compound-turbo setup is wastegated and blanket-wrapped, and the pair combine to force as much as 80 psi of boost into the engine. Feeding that much air demands serious fuel delivery, which is why the build carries a PPE dual fueler, a Fuelab lift pump, and Industrial Injection’s 5×18 race injectors. Behind it all, a reinforced 48RE automatic — built with a triple-disc converter, a manual valvebody, and a shortened output shaft — is tasked with putting all of it to the pavement without grenading.

Built to Fit, Not Forced to Fit

What separates this ‘Cuda from the usual diesel-swap spectacle is the fabrication philosophy behind it. Instead of hacking away at the factory firewall and inner fenders to cram the Cummins in, Weaver shaped the engine bay to flow around the diesel’s natural contours, so it reads as a factory-style install rather than a garage improvisation. That attention to detail is part of why the build gets passed around enthusiast forums and diesel meets years after it first appeared.

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