What do you think you need for the ATS turbo? Is it an 088 or 085 version? They use Garret turbos and most of the parts can be had through Typ4 (Russ) who's a member here, or many online places, but be careful... also many good local fuel injection and turbo shops would have the parts to overhaul any Garret turbo including this one. Cold side orings can be matched up at a hardware store or a Caterpillar dealer, and towcat mentioned a shop somewhere that carries some obsolete ATS parts, I can never remember who they are. The parts that are dealer only and NLA are the pedestal, and the cast iron up pipe and casting collector. ATS still has a downpipe to fit these turbos and a good exhaust shop *might* be able to fabricate one or in a pinch you could use flex tubing but that's probably a sub-par solution. As far as the fuel system, I don't know how the pump and injectors are on your son's 6.9 but there really isn't enough difference to justify the swap. A stock 6.9 pump may deliver slightly less useable fuel than a 7.3 pump due to the slightly smaller fuel delivery plungers (.0029" vs .0031") but the difficulty of the swap leads me to think that only a Moose pump or similarly "hot" injection pump is worth the effort. The injectors should probably be pop tested for spray pattern and opening pressure, and should be either replaced or reset unless they are all good and within 50-100 psi of each other. This aids in timing. Timing should be done with tools but aligning the scribe marks and timing by ear will be enough to make sure it runs passably without breaking things as long as the gears have not jumped timing. The thing I'd be most concerned about on turbocharging an older 6.9 is that if it has a lot of blowby expect the turbo to make it worse, not saying you shouldn't do it but expect any weak spots to show up more. Speaking of weak spots...how many miles on the engine? Are the head gaskets original? If not how many years on them? If you trust the head gaskets, and the engine is in pretty good health 10-12 psi is plenty for stock bolts and easy for that ATS non gated system if the fuel is turned up sufficiently and there is enough load on the engine. Anything above that you need head studs and probably an intercooler or water injection. By the way a pyrometer is mandatory and should never go above 1250 degrees if in the crossover pipe not more than 3" from the exhaust manifold or tapped into the manifold itself, not more than 1050 in ATS stock location and somewhat cooler than that like 900 or less if on the cold side of the turbo. Good luck, I LOVE my ATS setup, sounds awesome with the straight 4" pipe.
