What size Battery do you need for a 1957 Chevy 283 12 volt?

Any battery that will fit within the mount and the posts are orientated correctly will work. I would recommend you get the largest CCA that will fit. You may have to install a battery height extender, modify the hold down, and you may have to replace the battery cables. Make sure there is clearance for the hood. Anyplace that sells batteries can help you. The Super Start Battery part number 24EXTJ sold at O'Reilly's should fit.