Also take into consideration the fact that your frame rails are way narrower than the GMT400 trucks. You'll need to install a 6.2L exhaust manifold on the driver's side, and raise the whole engine up about 1/2" to make room for the turbo manifold on the pass side. You'll then either need to run your exhaust outside the frame rail through the inner fender, or install a 2" body lift to make room for the exhaust to run inside the frame rail. You'll need to make a custom crossover pipe that bends up and away from the front drive shaft to prevent contact there as well.
You can use your TBI fuel pump to feed the 6.5L, thats what I do with the turbo 6.2L in my K5. I use a TBI fuel filter on the frame rail in addition to the 6.5L fuel filter on the back of the intake. Some custom bending / flaring will be required to make the lines to fit everything up.
Installing the DS4 injection is possible, but it is still a considerable undertaking. As mentioned above, I would highly recommend a switch to a DB2 mechanical injection system and stand alone glow plug controller.
If you are running an automatic, your only options would be to run a 700r4 or find a stand alone controller to run a 4L60e/80e behind the engine. As mentioned, a diesel 700r4 is not the same as a gas version, it will need a different govenor and torque converter. The electric transmissions just require a different torque converter. You won't be able to use the old school vacuum lockup controllers for the torque converter either, as the diesel engine makes no vacuum (also requiring a switch to hydroboost brakes). You'll just have to wire the trans to lock up in 4th gear and stay locked up unless you hit the brakes.
Of course, you'll have to take cooling into consideration. These engines require an insane amount of cooling. You'll absolutely need to upgrade the rad to at least a 6.2L rad, even more with the turbo engine if you plan to do any towing or offroading where you might get the rad dirty. I've overheated my 6.2L at -30F before, and thats with all the best cooling components installed.
Also, before you buy that 6.5L, you need to check on a few things, even being low mileage. Pull the oil pan off and inspect the main bearings. These engines are famous for cracking along where the main fasteners are threaded in. Check for oil sprayers installed in the mains, those blocks are considerably weaker than the earlier or later blocks. Check the timing chain, make sure it isn't too sloppy. I have yet to touch a 6.2L or 6.5L that had a timing chain within tolerance. Also check on the harmonic balancer, it should be crack free, not missing any chunks or bulging out anywhere. The harmonic balancer is critical on these engines and must be checked on a very regular basis to be changed at the first sign of trouble. Also check on the turbo, make sure there is no lateral movement in the spindle, a little front to back is ok.
All in all this is not a quick or overly easy swap. Changing to a N/A 6.2L isn't half bad, but the turbo adds a fair bit of complication and expense. If you have everything laid out, planned and considered ahead of time, you can easily swap things over pretty quick though.
thats it right there.
