Yup: Double the Wattage
Just make sure you only connect one to the motherboard (i.e. use one for mobo and a few othe rbits and one for drives, screen etc) oh and splice the power on leads together. Wires 14 or 15 i think but check 1st - there is some mor einfo on it. NEVER EVER run a power supply with no load though or it wont be happy!