What is wrong with this radiator support...

So that is where mine is set to... Is this the right radiator support or not? I would expect a later V8 to wider so it would need to be squeezed to the center too far like this one is.... like @pishta said.
OK, it took me a minute to figure out what you're saying, but yeah, if it has a 65 radiator support, the side panels would have to be moved in to make the radiator opening 63 sized. Your driver's side looks like the right piece to me (just eyeballing). What does your passenger side piece look like? Because the 63 panel on that side does look different than later ones.

Edit: Here's a 65 Barracuda radiator support I found on ebay:
65 barracuda radiator support.jpg