cooling overhaul

First road trip in our '06 L6 6-spd last week. It ran at 210 most of the time, but started creeping up a little bit if we went over 55mph. It never got anywhere near the red, just a little past 210. But... it blew out coolant twice. Both times we had been going 70mph and it was 95° outside...

I've commented in a thread or two about my 1999 4.0 M/T needing a cooling system overhaul. This isn't one of those "if it ain't broke, don't fix it" situations. My sh*t is really broke. I believe I've read just about every post in every thread about cooling systems and haven't run across this...