Good writeup. Now who wants to tear one of these things down and rebuild it in the garage? The right way to do it is like Mel's guy does with the expensive calibration tools but a lot of the guys with Government Motors engines are too cheap to do all that. There's one guy here Dieseldummy who is by no means a dummy and has done some of his own calibration work on a 6.2 DB2 pump. I'm sorely tempted to play with this old 6.9 core I have, to swap a DB4 head on it, but I worry the chances of me getting everything right probably mean money and time flushed down the toilet we shall see.