BadCon

If he's like any other tuner, he is going to set the fan to come on full blast by 200 degrees, and some level other then full starting around 180 or 190. This is done to help reduce heat soak and reduce cylinder head temperatures and is normal. However you can resolve the issue with a colder thermostat, which will lower the general day to day operating temperature 10-20 degrees and keep the fans out of their now lowered activation zones until you start pushing it. The factory thermostat on the 5.0 is 190, and I'd suggest the Reische 170. It will lower your day to day temperatures to about 185-190 around town and on the highway, and will not effect open/closed loop, throw a code, or the amount of heat you get in the cab. I can't remember where I read this, but every 10 degree reduction in cylinder head temperatures equals about 1 octane increase in effective knock reduction.

I'm not a whipple guy, but when I loaded a custom tune on my Roush truck the fans would kick on full blast by 200 degrees, but my truck would see normal operating temps between 200-205 with the factory t-stat and all my cooling mods. This meant the fans were always screaming, and it was rather annoying. One Reische t-stat later and the issue is resolved, and I've noticed no changes in drivablity. I can't comment on heat soak as its winter...even here in Texas, so I'll reserve my judgement for summer time.