I need a new radiator for my 63 dart

Hey there, want to buy a new radiator for my 63 dart. I have a slant six that is mildy built. Wondering if i can just put a v8 aluminum radiator in it or if the 6's were different for any reason. Someone said that the 6's maybe had a smaller lower input hole. Also any clue on what size I need. Found one on ebay that says its 22". Does that sound right? Any info would be greatly appreciated. I may put a built up small block in it someday so I was thinking about just getting a v8 radiator.