Ord22,
The 6.5 is available in both turbo and non turbo. The new one I am installing is a non turbo. The non turbo bolts right up to the regular transmission.
Putting a turbo 6.5 in place of a 6.2 or 6.5 non turbo equipped truck can be done. I looked into putting a 6.5 turbo in but going that route is very expensive and requires a new electronic overdrive transmsion, new wiring harness for the engine and transmission, new drive shaft, new fuel tank to allow for the longer transmission, and the computer unit that is located under the rear passingers side seat. the transmission computer is not easy to find either.
The best way to have a 6.5 turbo in a HUMVEE is to pay a little more. I understand from a 6.5 turbo owner they run 70mph on the highway.