2x4 Pin question

Hi,
I am upgrading my power supply. I have an intel DZ77BH-55k. The motherboard says to use s 2x4 power adapter. I have been using a i7 3770k. I plan on doing minor overclocking. Do I really need a 2x4 adapter? Can i just use a 2x2 adapter and put in in the right side? If I need one, can you recommend a cheap power supply (under $85) that has a 2x4 power cord and can handle crossfire/sli? Will this supply work http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Thanks