Things may have worked out for DieselTechTom after all. Having discovered I needed a new turbo after only 57k miles--I opted to sacrifice some low end for mid range and get a Garrett Powermax turbo. I also replaced the braided oil feed with a rigid line, updated the drain tube to the new, much beefier version, replaced the backpressure sensor
and cleaned the EGR valve.:
The turbo was a big job for an old, fat guy with large hands and forearms. Reassembly is a puzzle where everything has to be installed in the correct order, or something won't fit later! Took me a while...
So what was the result? OK performance and high EGTs. Hmmm. Never occurred to me that a slightly larger turbo would cause my EGTs to go up markedly--if anything I expected to not reap the full benefit of a larger turbo, but would be happy with it. Some quick Binging gave me my answer--Powermax turbos need custom tunes to work properly.
Jody at DP-Tuning came up with a couple tunes for the 6.0 E350 diesel. I went with a 60hp tow tune to keep EGTs and ECT down, emphasize the mid range and activate the fan 5F earlier. He sent me the tunes via email and I installed them with my new SCT 3000 tuner.
The first used F250 transmission shift points and the van hated it.
The second used stock van shift points and was awesome. The EGTs have never been lower, low end is better than it was with the bad turbo and mid range is amazing. Pulling a steep hill near my place, I was able to accelerate (which never happened before) to 65, keep the EGT under 1000F, boost below 20psi and NO black smoke.
At this point everything seems to work together perfectly. I'm very happy with my $2000 "investment". The worst part was having to use a PC laptop to get the custom tunes on the SCT device. Took three years off my life at least.