Well, given gas prices, I'd be putting a new thermostat on as quickly as I could. Then you'd be getting up to temp, and a lot sooner. Significantly less fuel consumed. Remember, Ford wanted to get these trucks the best mpg they could so as to compete with bowtie and horny critter, and help their CAFE numbers. They'd not put an extra nail or screw on these when they made them. They have teams trying to wring the last lock washer out of production costs... a thermostat is there for a reason.
tom