[DanEC]

if this has already been covered I apologize as I haven't read all 5 or 6 pages of posts. Are you running vacuum advance hooked up to full time (not ported) a vacuum source. A working vacuum advance unit can make a very large difference in coolant temp on a big block Chevy - I've experienced it. I don't know why a Ford should be any difference. The additional timing at idle and cruise will greatly lower coolant temperatures.