Thank you for the pictures
@Motorcity Mustang and
@ib4stangs .
I am trying to figure out if I will be able to use the stock brackets. I got the new race seat and the spacing between bolts is 13.5" while the Mustang brackets are spaced 14". The issue then is that each bolt needs to be offset 1/4" so I don't see a way I can use the stock bracket without cutting most of it up or fitting another adapter between the seat and brackets, which will raise the seat too much. That said I am looking at something like the Wedge brackets:
https://wedgebrackets.com/ford-mustang-71-73-seat-brackets.html. They are expensive but it saves me the cutting and welding that would be needed to build the bracketry. If someone has a better idea I am open ears.