How long to bake pie?

I’m making apple pie and need advice about baking time and temp.

My oven’s thermostat and dial need repair so I can’t change temp mid-bake. Will it come out okay if I start (and keep) it at 350°? How long should I add to the bake time to account for the lower temp? I normally do 20ish minutes at 400° and then 65-70ish minutes at 350°.