GM stated that it successfully destroyed every prototype of the 4.5L Duramax V8, with one of them located in Sweden.

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      Nearly twenty years ago, General Motors was set to unveil a groundbreaking engine that could have transformed the pickup truck landscape, but that never came to fruition.

      The 4.5-liter turbodiesel V8, also called the Baby Duramax, was almost production-ready, even showcased in a Suburban concept at a SEMA show, and poised to set new standards in the half-ton truck market. However, after the 2008 financial crisis and GM's subsequent bankruptcy, the Baby Duramax project was abandoned. GM claimed all prototypes were destroyed, yet at least one engine has somehow surfaced in Sweden.

      This isn't just an exaggeration. The Baby Duramax was expected to deliver more torque than any other engine in a half-ton truck at the time, achieve better fuel efficiency than competitor engines with less output, and introduced technologies that wouldn't appear in sports cars for another decade. It was a remarkable engineering achievement seemingly ahead of its time. What might have been—and what could potentially still be—is intriguing, particularly as at least one prototype has escaped into the public domain. Are there others? How many? Where are they now?

      In the latest episode of The Drivecast, we delve into the Baby Duramax, codenamed LMK—what it was, what it might have become, and the prototype that made its way into the world.

      If you have any information about the LMK Baby Duramax, please contact us at tips@thedrive.com.

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      Full Transcript

      Caleb: All right, Joel. I’m thrilled to finally address this on a podcast. It consumed so much of my time while I was trying to uncover the current situation regarding the lost Duramax. Here we are, and it’s slightly ironic since you spent the last week in a Silverado EV Trail Boss. Quite a different vehicle, wouldn't you agree?

      Joel: Absolutely. We’re living in a vastly different world compared to 2008 and the LMK. I just had a Chevrolet Silverado EV Trail Boss, which is an electric truck with a large battery pack, heavy build, and impressive specs—775 pound-feet of torque and 725 horsepower. With 35s, it represents a real contradiction. We’ll review that later, but it’s ironic timing to talk about the Baby Duramax and its missed potential, especially considering how much the truck segment landscape has changed. Before we dive deeper, Caleb, can you provide some background on what we’re discussing, its history, and what happened to the engine that escaped destruction?

      Caleb: Sure! The 4.5-liter Duramax project began around the mid-2000s, destined to innovate in the competitive half-ton truck market, primarily consisting of GM, Ram, and Ford. Back in those days, the half-ton segment wasn't particularly impressive; Ford was offering the 5.4-liter Triton, which continues to face criticism today. GM was thinking ahead, aiming to develop a diesel engine for 1500-series trucks, which would outperform traditional small-block gas V8s. They designed one to fit where a small-block V8 would, amplifying fuel efficiency and providing 520 pound-feet of torque. They meticulously developed this engine which featured a hot-V turbocharger—technology that only appeared in sports cars like the Mercedes-AMG GT and Cadillac CT6-V Blackwing many years later. In essence, it was a remarkable feat of engineering worthy of recognition even today. However, when the 2008 financial crisis hit, GM's bankruptcy ended the project, leaving us only with stories about the engine. I managed to gather some first-hand accounts from those who had seen it, starting with Gail Banks.

      Joel: Before we delve further into the engine itself, I want to highlight some context from what you mentioned, Caleb, because it's crucial. This wasn't just about trucks. You pointed out that this engine could fit into various vehicles like the Escalade, Tahoe, Suburban, and Yukon—opening up a range of possibilities that could have led to an entirely different timeline. At that time, there were no small V8 turbodiesels or any turbodiesels at all in