Mechanical engines are fading further and further into the rearview mirror of heavy-duty trucking. As they do, more operators are asking the same question: does an electronic engine replacement make sense for my rig? The answer is often yes—it can dramatically improve fuel efficiency, add modern diagnostics, and enhance overall performance. At Kustom Truck, we’ve been helping fleets and owner-operators make this upgrade seamless for nearly 20 years with our Legacy Line of harness products, designed specifically for the critical engine-to-cab interface. Whether you're a fleet operator, mechanic, or truck enthusiast, understanding this process—and how our harnesses make it straightforward—can save you time and headaches. In this article, we'll break down what a mechanical to electronic engine conversion entails, especially as it pertains to cab interfacing, explain the role of our harnesses, and highlight why they're a go-to solution for replacing a mechanical engine with an upgraded electronic engine. As experts in engine swaps, we engineer and develop parts like mounting brackets, piping k