Since you're ready to ditch the whole drivetrain to go GM or something else, why don't you take a Yukon, remove the body from the frame, and strip the X5, and install the X5 body over the GM frame. The wheelbase of each truck is the same, 111in

Like that you will have a full frame capable of mega hp, and no need to fit the GM drivetrain.. It has been done many times by 4x4 guys.

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