You would most likely need a heat lamp, humid hide, cover the top almost completely except where the lamp is.. Put more than 2 hides in there because a 55gal will be very overwelming to a small BP. I would clutter it up with stuff. Crumpled paper, fake plants, plastic hides etc..
Everyone is going to tell you to start out smaller if you are getting a small BP. Being in such a big enclosure may cause it stress and it may not eat very well for you.
BUT there are things you can do to help the situation if all you have is a 55gal. Try to find an older, more established BP. Have the right temp/humidity gages (accurite weather station). Thermostat to control the under tank heat pad.
And I didnt even notice your avatar... You already have the BP? You may run into problems if you put it in such a big tank. 55gal are so tall it would be hard to reach down in there to clean it as well. You want it on display. If you do whats needed to ensure the snake is happy and stressfree, you will hardly ever see it anyway. BPs live most of their life in a little rodent burrow. Females rarely ever come out. Males will go looking for females dens during breeding season. Thats about as much as they travel out in the open.