* Engine Mounts: The 1-ton van engine and its accessories are likely significantly larger and heavier, and its mounting points will be in different locations compared to the Tahoe's engine bay. The Tahoe's frame and mounts simply won't be designed to accommodate it.
* Exhaust System: The van's exhaust system will be completely different and incompatible.
* Accessories: The accessories (alternator, power steering pump, etc.) might be different sizes and in different locations, creating further incompatibility.
* Transmission: Even if you managed to shoehorn the engine in, the transmission would likely be incompatible. The 1-ton van likely has a heavier-duty transmission designed for a much higher torque output.
While some engine swaps are feasible, this one presents far too many obstacles. The size and weight differences alone make it a highly impractical, if not impossible, project. You'd be looking at an extremely extensive and costly custom fabrication job – far exceeding the value of the outcome.
