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Absurd 2,500-HP GMC Sierra Sleeper Truck Hides a 10.3L V8 and Twin Turbos

Come for the unsuspecting race truck, stay for the crazy dyno clip with glowing pipes.
Nelson Racing Engines

Anyone can appreciate a modern, modest truck, and this 2017 GMC Sierra seems to fit the bill. It’s got a single cab, skinny tires, and a plain interior, though underneath, it’s anything but stock. That’s because Nelson Racing Engines ditched the factory power plant for a bespoke V8 that lays down 2,500 horsepower with help from two turbos and 10.3 liters of displacement.

It’s actually one of two that NRE is building, as Tom Nelson tells me. They’re both headed to the same customer who asked for one in red and one in white. Why anyone would need one of these—let alone two—is beyond me, but I’m glad someone does. And before you ask, the engine won’t pass SMOG, which isn’t a problem for the buyer since they live in a country that doesn’t require emissions testing.

The 632-cubic-inch big-block is force-fed by a pair of 88-millimeter NRE Mirror Image turbos. The blowers even have their own standalone oil system because they’re mounted so low. It doesn’t stop there, as Nelson says, “We also designed from billet some really trick water air intercoolers that came out like art and have their own cooling system in the bed of the truck.” There’s also what Nelson calls “one of a kind BAMF dual drive-by-wire throttle body intake manifolds”—I’ll let you figure out what that acronym stands for yourself.

You can tell how much work was put into doing everything right. It fits oh so snuggly into the engine bay, which is a big part of why the turbos are mounted behind the front bumper. If you look closely, you’ll notice that it even has a custom billet motor plate that serves as a serpentine drive, meaning it still has air conditioning. “We’ve been able to provide the factory ECU with the proper J language for it all to work,” Nelson tells me, adding that the factory dash works as intended, as does OnStar if it’s ever needed.

All this output gets sent through a Rossler Turbo 400 transmission with a Gear Vendors overdrive. Then, before it reaches the wheels, it makes its way to a custom nine-inch rear end that’s plenty stout. It’s one thing to build an engine that makes this much power; it’s another to support it with a properly strong drivetrain.

There’s nothing stopping the owner from driving this every day, at least from a mechanical standpoint. It’s sure to drink a lot of fuel, but if you’ve got the cash to build something like this, then that’s not a concern. It’d be a pretty big flex to take this to the grocery store, though as long as it gets driven, it doesn’t really matter where to.

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