Every single brand new car i've ever purchased in the last 20 years has run smack dab right at 210 degrees according to pulling the data through the OBD2 port. GM, Ford, Infiniti and a Honda. Doesn't matter if it's 5 degrees out, my two new DD's have always run right at 205-212 degrees right from day #1. However these are all Aluminum headed modern engines and i do beleive the higher temps could be desirable for catalytic efficiency as well. I've never actually seen any official documentation from Ford on the 5.0 as to optimum/desired 302 operating temp. I wonder if there is any coding in the ECU GFUB that might give a clue. I do recall conditions of operations being dependant on coolant temps. I'll take a peek later on.
I used to run my Fox with a 180 thermostat and it would run reliably at 185 degrees no matter what. In the spring/fall I never even needed the fan while moving to keep it at this temp. Drove it this way (with the 180 stat) for 20 years and when I tore it down for my build a couple years ago it looked pristine inside. based on the wear chart above, the difference between 180 and 200 really is negligible. I stuck a motorcraft stock tstat (192*) back in and now the car runs around 195-200 degrees. I might swap the 180 back in but i'm not losing sleep over it. I do have high-flow cats so maybe I should keep the warmer tstat in to protect them. Here in the northeast we just don't have the brutal heat that you folks in the south do. Other than the occasional heatwave, our temps are reasonable in the summer. I've done cruises where I am always moving and the Efan never even has to come on. When it does come on, I have my contour fan set to 70% max RPM and that's usually enough to keep it cool idling on a hot (for MA) day. Of course, everyone's experience is going to differ based on where they live and other factors.
I'm gonna go dig around to see if i can find documentation. Indy emailed me a bunch of stuff a long time ago I can sort through.