Is Bigger Better?

Ready to buy a radiator for my '68 hemi dart, about 620 hp. stick. It would just seem that a 26-inch would cool better than a 22-inch. If true, how dificult would it be to open up the core support to fit the 26-inch. Is this a common way to go? Or maybe get a 26-inch core support (say B body) and fit it into the dart?