Just reporting back. I've done a few trips either hauling a horse trailer across the state or the toy hauler further into the mountains. Everything is running beautifully. When towing, I am running my fan constant (blue-wire mod). I didn't try to push it without flipping the switch so coolant temp never got above 210-ish. It really feels like, if left to it's own, the fan engages wayyyy too late to be effective when towing. I recall the tuner (Vivian) telling me they had lowered the trip point for the fan on my tow tune as well but I've only seen it kick on when temps were above 220 (pre rebuild) which is too late. After the last trip, I seriously considered installing the 7.3L fan clutch but for now I'll just remember to flip the fan switch when towing and just leave it. I know there seems to be two camps on this and I don't think either one is wrong. I really do like the idea of the 7.3 clutch so I never have to think about it again.
When not towing, EOT/ECT are within a couple deg of each other if not identical. Even when towing (and fan is on), they stay within reasonable range of each other. Coolant pressure rises with temps and highest I saw was 14 before I kicked on the fans to bring temps back down. Normally hanging around 9-11psi.
EGTs do seem to run hotter than before. For towing, I did detune the ficm and put my tow tune on. It's too easy to get into danger zone w/ EGTs which is annoying but it's manageable.
Overall, I'm super happy with the results. Time will continue to tell but I'm hopeful the KDD heads and all the work I put in to do it right will translate into a truck that lasts for many more years to come.
As soon as I get time, I'll be doing another oil change (short interval after the new heads) and will clean out the IPR filter - mostly out of curiosity to see if it's still collecting crap and how much.
I also still have it on my todo list to install the PMF radius arm drop brackets (hoping to put a nail in the coffin of the caster induced wander) and replace some u-joints on the front drive line so I can use 4x4 without sounding like its going to drop the front end.
Oh, I forgot to mention. When camping, I like to tinker on things so I usually bring a bucket of small projects to do. This last trip, I installed my ham radio (finally), ran some tubing in the door seals and put some dynomat over the vent behind the back seat (drivers side because that was cut out and exposed and noisy). I'll be going back and dynomatting the whole back behind the seat and some of the firewall as well as the door panels. Just trying to add a bit of comfort for the longer road trips by getting rid of the freeway drone.