The injection pump adjustment is detailed HERE

This article is for ford 7.3's with the same Stanadyne DB-2 mechanical pump as the 6.2 NA and 6.5 NA Hummers use, so the details of this article are the same. I turned mine up 1/6th of one clockwise rotation. I wouldn't recommend going over that because a banks turbo or whipple kit suggests 1/4th turn. The added airflow of the K+N and exhaust is needed proir to doing the adjustment, otherwise your only gains will be in EGT's and black smoke. A Pyrometer is recommended so you can monitor the EGT, I do not have one yet, but will install one soon.

In addition to the article, I must say that the screw is hard to see and you definitely need a good mini-flashlight and a small mirror. A large socket and breaker bar on the crank bolt (sorry I can't remeber the size) to turn the engine over. It took me 2.5 hours to do this, I had to turn over the engine very slowly in small increments, then climb back up to see if I could see the screw. about a pint of diesel will spill out into the engine valley, I soaked it up with a rag when I was done. I thought it might airlock the injection system, but it did not, it fired up very easily after. The throttle cable bracket must be removed from the injection pump and a good quality allen set is needed.

Note that I am by no means a professional diesel mechanic, just good with most tools/mechanical things. I did this on my first try, with no help only an article on the internet I printed out. It was time consuming and frustrating at times, at first I swore I wouldn't reach it without removing the intake manifold, but in the end the intake did not need to come off. It is well worth the effort, if you can make friends from your area over at The Diesel Page you may get some free help from those who have done a few adjustments already.

Tony