I need a measurement on a 67 camaro

[sunoco67]

Can someone please provide me with a measurement. I am reinstalling the y braces after replacing the trunk floor pan on my Camaro. I may have tweaked the rear deck shelf a little bit so Im hoping somone can provide me with a measurement. The measurement im asking for is from the center of one hole in the y brace to the center of the seat belt hole or center of bolt.
Thanks in advance

[J2SpeedandCustom]

I have 2 in the shop both measure to 17 5/8 center to center.

[sunoco67]

Thank u so much now I can get back to welding the braces in.