The 1.600 showed up through one of td25's post from a shop manual. About 4 years ago I sold my diesel business of 20 years in SC. Moved to TN for semi retirement and started a new shop that hopefully my son will take over soooon. Regarding the drill rig, I came into this situation very late. This well drilling outfit has been a very good customer and has kept us very busy. After building several CAT deck motors, 7.3, 6.0, 6.4 and 3208's for them, they dropped this rig off that I have never seen. Here is the story I got; Ran it for 6 years, it had plenty of power. Started loosing about 400 rpm under full load and this was not acceptable for this application. The only people in this area at that time that would work on the dd was an actual dealership. They sold them on a rebuild, the problem continued. They ran it for about 6 months, carried it to a private shop. He sold them on bigger injectors and a new turbo; The problem continued. Then they spoke to the drill rig manufacture and they sold them on needing a new air end;And the problem continued. They parked it, bought a new rig and 2 years later they bring it to me to fix. Test ran and it seemed to have a restriction in air flow. Pulled the turbo and there were no problems, practically new. Pulled the blower, no problems there. The blower mounting gasket was bent over and pinched in one spot, may have been losing boost at that point. The inner cooler was partially stopped up apparently from a leaking oil seal at the turbo (gummed up). Repaired all these items. Running valves and injectors to see where they were at and here we are. They spent an excess of $50,000 before it got to my shop. Needless to say this is not a typical straight forward problem.