What temperature do you cook a pan of dressing at?

its not how long you cook a bird or what temp that matters, its the proper internal temperature. To determine done-ness of the bird , use a cooking thermometer.

And since i don't know how much your bird weighs, i cant answer the question properly as to what the temperature to roast it. Or how long .

But its stuffed you said and large. So i would guesstimate roast it at 400 degrees for 20 minutes, then turn the oven down to 325 degrees , cover the bird with a tent of foil loosely, continue roasting for an hour . using the cooking thermometer -Check the temp of the bird at a thick part - should reach 165 degrees. Also check the temp of the stuffing, should be 150- 160 degrees.

Continue to cook until the bird reaches those temps.