Help with Heating a big cage?

-I have a 4 foot long 4 foot tall and 2 foot wide.I use 2 heat lamps one is 75 watts and the other one is 50 watts I also use a heat mat. Is this enough or do I need a higher wattage bulb?I want the cage to be at 80-85.I have my room set at around 80 degrees (if that helps)that should be fine. the best thing to so is get some thermometers to make sure it isnt too hot or too cold. there needs to be a hot side and a cool side usually so you need two thermometers on both sides.depends on what your keeping in the tank