You can get a variety of shrouds for your car from NPD (National Parts Depot). You will need to know if you have a 2 core or 3 core radiator to order one, and will need to order the mounting brackets separately.
65 FB "Get your facts straight first, then you can distort them as much as you wish!"
The circular opening dia is 18" and it's 19 1/2" from mounting edge to mounting edge. I don't have pics, but if your interested I will borrow a camera and take some. Again, this is a brand spanking new repro. I'm pretty sure I've got the new repro mounting brackets and bolts too (will have to search for them).