You're in a hole and digging with this IP. The kits to rebuild come up pretty much all the time on evil bay. They are the same for the 6.9/7.3 the GM 6.2/6.5 and even 5.7. The problem is when you really tear into these things getting them calibrated right isn't too easy without the fancy equipment and training a turbo and injection shop has. That being said almost everyone here leaves the IP rebuilds to the pros but by the same token a lot of GM guys balk at spending 300-500 for a new IP and will at least do a basic rebuild(seals etc). You might talk to Justin(dieseldummy) if you're dead set on doing it. If not I think Pensacola diesel is selling the IPs for $285 outright no core these days. I don't know what your best option is. The kit is cheap and from what the GM guys say messing with a pump isn't as bad as us Ford guys make it out to be. You could learn a lot from the experience, but bear in mind you could trash the core and make it worthless. Worse still even having that governor cover off you could cause the engine to "run away" To prevent this, get a big hardbound book or smooth clipboard that fits snugly over the air intake horn, and if that engine tries to run uncontrollably you can kill the air supply so it won't destroy itself with runaway. You need to take the intake screen off as well for this to work well. You cannot control the engine with the ign. switch in a runaway situation. Also I think some guy posted a PDF on DB2 specs and overhaul procedure a few months back, I never looked at it, sounded like it might be real technical, I think it was a military manual. You know all those Humvees in the armed forces have DB2s as the military is exempt from many of our emission control standards and thus they never went over to the POS DS4 pumps that the newer 6.5 TD engines had in the US. Good luck please keep us posted. Lots of pics please if you do tear it down. I have a core sitting in the garage that no one wants and I'd like to play with, maybe swap a DB4 head on it and really play hehe.