Interior dimension-64 to 66 vs. 67-69 difference?

[Deucemopar]

For A-body Barracuda. We may need to replace current roll bars with roll cage. Some places sell moly 10 pt kits for 67-69 Barracudas. We have 65. I know there's still some customization/cutting/fabbing.

But as a headstart, a kit would be great. Of course, only if interior dimensions are close enough.

Any thoughts, experience, input?

Thanks very much for help!