Looks like someone slipped some cool-aid into your coolant system...
I hope you get that coolant issue figured out. It's quite the head-scratcher.
Okay, thought I had sense of this for a minute but now less sense.
Idled the truck for 3+ hours
Hour 1 - 195
Hour 2 - 203
Hour 3 - 202/203
Hour 3.5 - 202/203
Test drive - 222, currently pulled over letting it cool down
for background, this is my first turbo intercooled IDI build, usually they always run cool not hot.
Could the intercooler blocking the radiator be making this much of a difference? There’s trucks in Texas and Cali running intercooler I can’t see that
I don’t have the fan shroud on, wouldn’t think it would make this drastic of a difference but it’s what I’m going to try next.
EGTs are good - 300/400