Can someone here tell me how wide a 65 rear trunk brace should be?

[Coupe]

I am rebuilding my trunk and before I start to stretch things to fit my new trunk brace in place I want to be sure it is not made wrong. Does anyone know how wide the RTB should be ?

Or, do you know what the proper width between drop offs should be? I know I can use the gas tank to set the trunk floor, but I need to get the RTB in place first.

 

[Coupe]

This is the piece in question. Dynacorn does not show a width for this piece..

They do for the ragtop, but for some reason it is wider than what I have already?

 

[Dennis Harrelson]

My original one measures 53", maybe 53 1/16".