If the inner header ( the part inside the cab ) is still good it is possible to recreate the inner brace by fabricateing 2-3 inch pieces to re make the brace then make and weld in the outer skin. I have started this process, it's going to be a lots of work. How do I post pics ?

 

Here are some pics of a ongoing roof repair , replacing the inner header brace and removing the drip rail #ad
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Yikes!! I replaced the entire roof on my 56. I found a nice used one. You can see what I did on the link below, towards the end of the thread. Good luck. I think you can get a steel top lid now but it used to be you could only get a fiberglass one.
https://www.ford-trucks.com/forums/1475171-56-f-100-basket-case-build.html

 

Oops just realized your is a 53-55. my roof is a 56.

 

still have the cab? In next door in wa state. and am looking for a solid cab

 

Sorry, cab is gone.......